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Gnaphalium affine is an annual herb with a stem about 10−40 cm in length, covered with white thick cotton hairs. The leaf is oblanceolate or obovate, about 5−7 cm in length and 11−14 mm in width, usually with only one vein. The flower is capitulum that densely forms corymbs at the top of the branches, and is involucrally bell-shaped with 2−3 layers. The outer layer is obovate or spoon-shaped, the inner layer is long and spoon-shaped; the female flowers are very common, the corolla is tubular, the top of the corolla is enlarged with 3-tooth, and the lobes are glabrous.
Gnaphalium hypoleucum is an annual stout herb with an erect stem, about 10−40 cm in length. The leaf is linear, about 8 cm in length and 3 cm in width, usually with only one vein, which is obviously visible on the top but not on the bottom. The flower is capitulum that densely forms corymbs at the top of the branches, and is involucrally bell-shaped with four layers. The outer layer is obovate, the back surface is covered with white cotton wool, the inner layer is linear, the top is pointed or acute, and the back surface is usually glabrous. The male flowers are very common, the corolla is filiform.
Gnaphalium japonicum is an annual delicate herb with a slightly erect stem, about 8−27 cm in length. The leaf is sword-shaped linear, about 3−9 cm in length and 3−7 in width, covered with sparse hairs above and thick white cotton hairs on the bottom. The flower is compound capitulum, and forms radial or astral leaflets. The total bract is nearly bell shaped, the outer layer is broadly elliptic, membranous, reddish brown. The middle layer is obovate oblong, and the upper part is reddish brown. The inner layer is linear, and the top is blunt and reddish brown.
Gnaphalium liebmannii, known as 'gordolobo' in Mexico, is an annual herb, about 10−150 cm in length. The leaf is narrowly elliptic or oblanceolate, about 2−9 cm in length and 0.5−1.5 cm in width, corolla, tomentose, margin smooth, and sessile. The flower is corymb and bell-shaped, and 3−9 mm in length, 2.5−7 mm diameter.
Traditional applications
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In China, the edible history of G. affine has been going on for thousands of years. As early as the Jin Dynasty, G. affine had been used together with glutinous rice to make cakes for human consumption (Fig. 1). Not only Chinese, the Japanese also used it for cooking porridge, and gradually people found that G. affine has certain pharmacological effects. To date, hundreds of species in Gnaphalium are found across the worlds, several of them have been recorded as traditional medicine in Asia, including China, Japan, and Korean, as well as countries in America (Mexico and Argentina). Most of these reports are related to the management of rheumatism, cough, and asthma. Additionally, some species are also used to treat bacterial and fungal infections, diarrhea, cancer, respiratory infections, and several other conditions (Table 1). In China, several registered drugs have been developed from Gnaphalium species, such as 'Fufang Fuercao Heji (复方佛耳草合剂)', containing G. affine as the main component, and used for the management of chronic obstructive pulmonary diseases (COPDs)[6]. Recently, G. affine can also be used as a vegetable for making spices and functional yogurts[7]. Apart from the medical and edible values, G. affine is also used as natural dye for silk coloring in Yunnan, China.
Figure 1.
The morphology of the Gnaphalium affine and its processed products. (a), (b) The overground part of G. affine. (c) The pastry of G. affine, called qingtuan, also known as Qingming food.
Table 1. Ethnopharmacological uses of reported Gnaphalium species.
Gnaphalium species Country Ethnopharmalogical uses Reference G. affine China, Mexico,
Latin AmericaPhlegm-removing, anemopyretic cold, antibacterial, bronchitis, chronic obstructive pulmonary diseases, antihypertensive, ulcer, antitussive, expectorant, antiasthmatic, bronchial asthma, respiratory disease, diuretics, antipyretics and antimalarials, wound, backache, coronarism. [8−24] G. hypoleucum China Inflammation, cough, gout, expectorant. [25] G. polycaulon China Clear heat and dampness. [26] G. japonicum China Promoting blood circulation to relieve pain, promoting dampness, treating acne, irregular menstruation, abdominal pain and dysentery during menstruation, clearing away heat and toxins. [27,28] G. adnatum China Treat Helicobacter pylori. [29] G. uliginoshisum Russia, Bulgaria Hypertension, thrombophlebitis, venous thrombosis, ulcer. [30,31] G. stramineum Guatemala Gastrointestinal diseases. [32] G. gaudichaudianum Latin America, Argentina Subcutaneous mycoses, expectorant, hemostasis. [33,34] G. liebmannii Mexico Asthma, cough, bronchitis. [35] -
There are multiple previous studies focusing on the chemicals in Gnaphalium species. To date, 257 compounds have been identified and characterized. The existing literature indicates the existence of multiple components, predominantly in flavonoids, phenolic acids, alkaloids, and terpenoids. Some of these components are directly or indirectly attributed to the pharmacological activities of plants in the genus Gnaphalium. According to previous research, the chemical studies of the genus Gnaphalium have mainly focused on G. affine, G. hypoleucum, G. sylvaticum, G. undulatum, G. oligandrum, G. pellitum, G. oxyphyllum, and G. adnatum. Here, the structures and other information of these identified compounds are summarized in Figs 2−12 and Table 2, respectively.
Table 2. Compounds isolated and identified from the Gnaphalium L.
No. Compound Source Reference Flavones 1 Apigenin 4'-O-β-D-(6''-E-caffeoyl)-glucopyranoside G. affine [3,5] 2 Gnaphaloside A G. tranzschelii [5] 3 Apigenin-7-O-β-D-glucopyranoside G. tranzschelii, G. luteoalbum [3,5] 4 Chrysoeriol-7-O-β-D -glucopyranoside G. uliginosum [3] 5 Apigenin-7-O-β-D-glucuronic acid methylester G. affine, G. hypoleucum [5,38] 6 Apigenin G. affine, G. hypoleucum [36−38] 7 Luteolin-4'-O-β-D-glucopyranoside G. affine, G. cheiranthifolium, G. hypoleucum,
G. luteoalbum[37,38] 8 5-hydroxy-4',7-dimethoxyflavonoid G. affine [38] 9 Acacetin G. affine [38] 10 Luteolin G. affine, G. hypoleucum, H. polycaulon,
G. luteoalbum, G. rufescens, G. sylvaticum,
G. oxyphyllum[36−38] 11 Chrysin G. affine [38] 12 5-hydroxy-6,7,3',4'-tetramethoxyflavone G. affine [39] 13 Luteolin-7-O-β-D-glucuronide methyl ester G. hypoleucum [3] 14 6-Hydroxyluteolin-7-O-β-D-glucopyranoside G. hypoleucum, G. affine, G. tranzschelii [5,40] 15 Acacetin-7-O-rutinoside G. affine [3] 16 Eupafolin-7-O-β-D-glucopyranoside G. affine [3] 17 5,7,4'-trihydroxy-6,3'-dimethoxyflavone G. luteoalbum [3] 18 6-MethoxyLuteolin G. uliginosum, G. tranzschelii [3,5] 19 Luteolin-7-O-β-D-glucopyranoside G. luteoalbum, G. hypoleucum [3,5] 20 Apigenin-4'-O-β-D-glucopyranoside G. affine [3] 21 5,7,4'-trihydroxy-3',5'-dimethoxyflavone G. sylvaticum [3] 22 Linarin G. hypoleucum [3] 23 Luteolin-7-O-β-D-glucuronide G. hypoleucum [3] 24 Acacetin-7-O-β-D-xylopyranosyl-[α-L- rhamnopyranosyl]-β-D-glucopyranoside G. hypoleucum [3] 25 Luteolin 4'-O-β-D-(6''-E-caffeoyl)-glucopyranoside G. hypoleucum, G. affine [3,5] 26 5,7,3',4'-Tetrahydroxy-6-methoxyflavonoid-7-O-
β-D-(6''-E-caffeoyl)-glucopyranosideG. tranzschelii [5] 27 Luteolin 7-O-methyl ether G. rufescens [5] 28 5,7,3',4'-tetrahydroxy-6-methoxyflavonoid-7-O-β-
D-glucopyranosideG. tranzschelii [5] 29 5-hydroxy-7,8-dimethoxyflavone G. pellitum [5] 30 Hispidulin G. antennarioides [5] 31 Velutin G. gaudichaudianum [5] 32 5,8-dihydroxy-6,7-dimethoxyflavone G. gaudichaudianum [5] 33 Hispidulin 7-O-β-D-glucopyranoside G. antennarioides [5] 34 Jaceosidin G.luteoalbum, G.tranzschelii [5] 35 3,5,7,4'-tetrahydroxy-3'-methoxyflavonoid-7-O-β-D-glucopyranoside G. tranzschelii [5] 36 8-O-(2-methylbutyryl)-5,7,8-trihydroxyflavone G. robuscum [5] 37 8-O-[(Z)-2-methyl-2-butenyl]-5,7,8-trihydroxyflavone G. robuscum [5] 38 Eupatilin G. affine [39] 39 5,7,4'-Trihydroxy-3'-methoxyflavonoid-
7-O-β-D-(6''-O-caffeoyloxy)-glucopyranosideG. affine, G. uliginosum [38] 40 Apigenin 7-O-β-D-(6''-E-caffeoyl)-glucopyranoside G. affine [3,5] Flavonols 41 5,7-dihydroxy-3,8,4'-trimethoxyflavonoid G. hypoleucum, G. affine [38,40] 42 Tiliroside G. adnatum [41] 43 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone G. affine, G. hypoleucum [2] 44 Kaempferol 3-O-β-D-(6''-O-coumarin)-glucopyranoside G. affine [42] 45 Isorhamnetin-7-O-β-D-glucopyranoside G. affine [38] 46 Quercetin 4'-O-β-D-(6''-E-caffeoyl)-glucopyranoside G. hypoleucum, G. affine [3,5] 47 Isorhamnetin-3-O-β-D-galactopyranoside G. uliginosum [3] 48 Patuletin-3-O-β-D -glucopyranoside G. uliginosum [3] 49 5,7,3',4'-Tetrahydroxy-3-methoxyflavonoid G. indicum [3] 50 5,7-dihydrox-3,8-dimethoxyflavone G. gracile [3] 51 3-Methoxyquercetin G. gracile [3] 52 7-Methoxyquercetin G. pellitum [3] 53 5,8-Dihydroxy-3,6,7,4'-tetramethoxyflavonoid G. affine [42] 54 Quercitrin G. affine, G. sylvaticum [5] 55 8-O-(2-methylbutyrate)-5,7-dihydroxy 3-methoxyflavonoid G. robustum [3] 56 Quercimeritrin G. hypoleucum [43] 57 Quercetin-3-O-β-D-galactopyranoside G. hypoleucum [43] 58 5-hydroxy-3,7-dimethoxyflavone G. uiscosum [42] 59 Rhamnetin G. pellitum, G. affine [5,38] 60 Quercetin G. affine, G. gracile, G. hypoleucum, G. polycaulon,
H. pellitum, G. sylvaticum, I. G. uniflorum[36−38] 61 Kaempferol-3-O-β-D-glucopyranoside G. affine, G. uniflorum [5,38] 62 5-Hydroxy-3,6,7,8,4'-pentamethoxyflavone G. affine, G. hypoleucum [38] 63 5,6-dihydroxy-3,7-dimethoxyflavone G. affine [38] 64 Baicalein-7-O-β-D-glucopyranoside G. tranzschelii [5] 65 Isokaempferol G. dioicum [5] 66 Quercetin 4'-O-β-D-glucopyranoside G. affine, G. hypoleucum [5,40] 67 Isoquercitrin G. stramineu, G. sylvaticum, G. tranzschelii, G.uniflorum [5] 68 Quercetagetin G. affine [5] 69 Quercetin 3-O-β-D-galactopyranoside-4'-O-β-D-glucopyranoside G. uniflorum, G. affine [5] 70 Quercetagetin 7-O-β-D-glucopyranoside G. affine [5] 71 Isorhamnetin G. affine, G. hypoleucum [5] 72 3,5,7,4'-tetrahydroxy-3'-methoxyflavone-3-O-β-D-glucopyranoside G. tranzschelii [5] 73 3,5,7,3',4'-Pentahydroxy-6-methoxyflavone-3-O-β-D-glucopyranoside G. tranzschelii [5] 74 Gnaphaliin B G. affine, G. liebmannii [5] 75 3,5-dihydroxy-6,7,8-trimethoxyflavone G. chilense, G. microecephalum, G. robustum [5] 76 3,5-Dihydroxy-6,7,8,4'-tetramethoxyflavone G. affine [5] 77 5-Hydroxy-3,7,8-trimethoxyflavone G. affine, G. robustum, G. obtusifolium [5] 78 5-hydroxy-3,6,7,8-tetramethoxyflavonoid G. affine, G. hypoleucum,G. undulatum [5] 79 Gnaphaliin A G. affine, G. gracile, G. lanuginosum,
G. liebmannii, G. obtusifolium, G. robustum[5] 80 5,7-Dihydroxy-3-methoxyflavonoid G. gracile, G. robustum [5] 81 8-O-(2-methyl-2-butenyl)-5,7-dihydroxy-3-methoxyflavonoid G. robustum [5] 82 5,7-dihydroxy-3,6-dimethoxyflavone G. wrightii [5] 83 5,8-dihydroxy-3,6,7-trimethoxyflavone G. affine, G. gaudichaudianum [5] 84 5,7-Dihydroxy-3,6,8-trimethoxyflavone G. affine, G. elegans [5] 85 5,7-Dihydroxy-3,8,3',4'-tetramethoxyflavone G. affine [5] 86 3,5,7-trihydroxy-6,8-dimethoxyflavone G. obtusifolium [5] 87 5,7,8-Trihydroxy-3-methoxyflavonoid G. robuscum [5] 88 Quercetin 3-methyl ether G. gracile, G. indicum [5] Chalcones 89 2',4',4-Trimethoxy-6'-methoxychalcone G. affine [5] 90 Gnaphalin G. affine, G. cheiranthifolium, G. multiceps,
G. purpurascens, G. luteoalbum, G. hypoleucum[5] 91 2',4,4'-trihydroxy-6'-methoxychalcone G. affine [38] 92 4,4',6'-Trimethoxy-2'-methoxychalcone G. affine [38] 93 2',4'-dihydroxy-4,6'-dimethoxychalcone G. affine [38] 94 2'-hydroxy-4,4',6'-trimethoxychalcone G. affine [38] 95 4,2',4',6'-Tetramethoxychalcone G. affine [38] 96 2',4,4'-trihydroxy-6'-methoxychalcone-4-glucopyranoside G. affine [3] Flavanones 97 Naringenin-7-O-β-D-(6''-E-caffeoyl)-glucopyranoside G. affine [42] 98 Taxifolin G. affine [42] 99 Dihydroapigenin G. affine [38] 100 Pinocembrin G. purpurascens [5] 101 Wogonin G. affine [38] 102 4'-Hydroxy-5-methoxy-7-O-β-D-glucopyranosyl-dihydroflavanone G. hypoleucum [43] 103 7,4'-Dihydroxy-5-Methoxydihydroflavonoids G. hypoleucum [43] 104 5,7,3',4'-tetrahydroxyflavone G. affine [42] Triterpenoids 105 β-Amyrin G. affine [5,38] 106 β-amyrin acetate G. affine [38] 107 Oleanolic acid G. affine, G. hypoleucum [38] 108 Friedelin G. affine [38] 109 α-Amyrin G. affine [5,38] 110 Ursolic acid G. affine, G. hypoleucum [38] 111 α-amyrin acetate G. affine [38] 112 Faradiol 3-O-palmitate G. affine [44] 113 19α-hydroxy ursolic acid G. affine, G. hypoleucum [38] 114 2α,3α,19α-trihydroxy-28-norurs-12-ene G. affine [38] 115 Taraxasterol G. affine [38] 116 Taraxasterol acetate G. affine [5,38] 117 Lupeone G. affine [38] 118 Betulonic acid G. affine [44] 119 Betulinic acid G. affine [5] 120 Squalene G. gaudichaudianum [5] Diterpenoids 121 Ent-pimara-8(14),15-dien-3a,19-diol G. affine [45] 122 Ent-pimara-8(14),15-dien-3α-ol G.affine [38] 123 Ent-pimara-8(14),15-dien-19-ol G. affine [38] 124 Ent-Pimara-8(14),15-diene-19-ol G. gaudichaudianum [5] 125 Ent-pimara-8(14),15-dien-19-oic acid G. gaudichaudianum [5] 126 Ent-pimara-8(14),15-dien-18-oic acid G.gaudichaudianum [5] 127 Ent-Pimara-8(14),15-diene-3α,19-diol G. gaudichaudianum [5] 128 Sclareol G. gaudichaudianum [5] 129 8α,13α-Diacetoxycinnamyl alcohol G. gaudichaudianum [5] 130 8-epi-Sclareol G. undulatum [5] 131 8-epi-Eni-sclareol G. gaudichaudianum [3] 132 Kaur-16-en-19-oic acid G. gaudichaudianum, G. inornatum, G. rufescens [5] 133 Methyl kaur-16-en-19-oate G. gaudichaudianum [5] 134 3α-hydroxykaur-16-en-19-oic acid G. gaudichaudianum [3,5] 135 Methyl 3α-hydroxykaurl-16-en-19-oate G. gaudichaudianum [5] 136 11β-Acetoxycoel-16-ene-19-oleic acid G. rufescens [5] 137 Methyl 3α-acetoxycol-16-ene-19-oate G. gaudichaudianum [5] 138 3α-Acetoxycol-16-ene-19-oleic acid G. gaudichaudianum [5] 139 Ent-Kauran-16-ene G. undulatum [5] 140 Ent-Kaur-16-en-19-al G. undulatum [5] 141 Ent-Kaur-16-en-19-oic acid G. affine, G. graveolens, G. oligandrum, G. pellitum,
G. undulatum, G. oxyphyllum, G. liebmannii[5] 142 15α-hydroxy-ent-kaur-16-en-19-oleic acid G. undulatum, G. viscosum [5] 143 11β-acetoxy-ent-kaur-16-en-19-oleic acid G. pellitum [5] 144 (−)-16-Kaurene-19-oic acid G. affine [3] 145 (−)-Methyl kaur-16-en-19-oate G.gaudichaudianum [3] 146 (3α,4α)-Kaur-16-en-18-oic acid-3-hydroxy-methyl ester G. gaudichaudianum [3] 147 3α-acetoxykaur-16-en-19-oic acid Me ester G. gaudichaudianum [3] 148 Ent-pimar-15-ene-8α,19-diol G. gaudichaudianum [5] 140 Ent-pimar-15-ene-3α,8α-diol G. gaudichaudianum [5] 150 Zoapatlin G. hypoleucum, G. affine, G. oxyphyllum,
G. liebmannii, G. viscosum[40] 151 Ent-3β-hydroxykaur-16-en-19-oic acid G. affine, G. viscosum [38] 152 (−)-11β-Acetoxy-16-kaurene-19-oic acid G. affine [3] 153 Kauranol G. rufescens [5] 154 Ent-Kaur-9(11),16-en-19-oic acid G. oligandrum, G. undulatum [5] 155 Sylviside G. sylvaticum [5] 156 Carnoside G. sylvaticum [3] 157 15β-hydroxy-Wedeliaseccokaurenolide G. undulatum [5] Sesquiterpenoids 158 Gemamane D G. oligandrum [5] 159 (2E,6Z)-7,11,11-trimethylbicyclo[8,1,0]undec-2,6-diene diterpene G. oligandrum [5] 160 γ-Cadinene G. affine [46] 161 (E)-β-Farnesene G. pensylvanicum [36] 162 Irisone G. pensylvanicum [36] 163 (−)-β-Elemene G. affine [48] 164 α-Gurjunene G. affine [48] 165 Trans-Caryophyllene G. affine [21] 166 α-Humulene G. affine [48,49] 167 δ-Cadinene G. affine [48] 168 α-elemol G. affine [48] 169 β-selinene G. affine [8] 170 γ-Gurjunene G. japonicum, G. affine [49] 171 Corchoionol C G. affine [38, 50] 172 Caryophyllene oxide G. affine, G. japonicum [51] 173 6,10,14-trimethyl-2-Pentadecanone G. affine [52] 174 Nerolidol G. affine [51] 175 1,5,5,8-Tetramethyl-12-oxabicyclo[9.1.0]dodeca-3,7-diene G. affine [51] 176 Aromadendrene G. affine, G. japonicum, G. pensylvanicum [8] 177 7R,8R-8-hydroxy-4-isopropylidene-7-methylbicyclo[5,3,1] undec-1-ene G. japonicum [46] Monoterpenoids 178 α-Terpineol G. affine [21] 179 Linalool G. affine [21] 180 p-cymene G. affine [21] 181 m-cymene G. affine [48] 182 Pulegone G. affine [52] Phenolic acids 183 Protocatechuic acid G. affine [46] 184 Caffeic acid G. affine [46] 185 Ethyl Caffeate G.affine [38] 186 Ethyl protocate G.affine [38] 187 Trans caffeic acid G. tranzschelii [5] 188 Caffeic acid ethylene ester G. hypoleucum [40] 189 Eugenol G. affine [36, 21] 190 Coniferylaldehyde G. affine [38] 191 P-hydroxycinnamic acid G. affine [38] 192 Methyl cinnaminate G. hypoleucum [47] 193 Isovanillin G. affine [38] 194 Isovanillic acid G. affine [38] 195 3',5-dihydroxy-2- (4-hydroxybenzyl) -3-methoxybibenzyl G. affine [44] 196 Everlastoside L G. affine [38] 197 Methyl p-hydroxycinolinate glucoside G. affine [38] 198 Acteoside G. affine [44] 199 1,4,5-tri-O-caffeoylquinic acid G. affine [38] 200 1,5-di-O-caffeoylquinic acid G. affine [38] 201 1,5-dicaffeoylquinic acid methyl ester G. affine [38] 202 1,3-di-O-caffeoylquinic acid G. affine [38] 203 3,5-di-O-caffeoylquinic acid G. affine [20] 204 3,4-di-O-caffeoylquinic acid G. affine [20] 205 1,4-di-O-caffeoylquinic acid G. affine [42] 206 Chlorogenic acid G. affine [46] 207 4-O-caffeoylquinic acid G. stramineum [5] 208 4,5-di-O-caffeoylquinic acid G. stramineum [5] 209 3,4,5-tri-O-caffeoylquinic acid G. stramineum [5] Steroids and sterols 210 Daucosterol G. affine, G. adnatum, G. hypoleucum [50] 211 Stigmasterol G. affine, G. adnatum, G. gaudichaudianum,
G. viscosum, G. oxyphyllum, G. liebmannii[38] 212 β-sitosterol G. affine, G. hypoleucum, G. inornatum, G. pellitum,
G. oxyphyllum, G. liebmannii, G. viscosum[38] 213 Stigmasta-4,22-dien-3-one G. affine, G. adnatum [38] 214 4-Cholesten-3-one G. affine [5] 215 3β-hydroxy-stigmasta-5,22-dien-7-one G. affine [5] 216 α-spinasterol G. affine [38] Alkaloids 217 Grossamiade K G. affine [44,38] 218 Aurantiamide acetate G. hypoleucum [3] 219 Matrine G. sphacelatum [5] 220 Scopolamine G. affine [5] 221 Anabellamide G. affine [38] 222 Patriscabratine G. affine [38] 223 Longumoside A G. affine [44] Others 224 Phloroglucinol G. affine [53] 225 3-methoxyphenol1-O-α-L-rhamnopyranosyl-4-
(1→6)-O-β-D-glucopyranosideG. affine [38] 226 2,3,5,4'-tetrahydtoxysilbene-2-O-β-D-glucopyranoside G. affine [50] 227 (Z)-3-hexenyl O-β-D-glucopyranoside G. polycaulon [5] 228 Gnaphalium A G. affine [54] 229 Gnaphaliol 3-O-β-D-glucopyranoside G. polycaulon [5] 230 Gnafaliol 9-O-β-D-glucopyranoside G. polycaulon [5] 231 (+)-Pinenutol G. pellitum [5] 232 Panamin G. hypoleucum [40] 233 Tithoniamide B G. affine [50] 234 4'-Hydroxydehydrogenase G. hypoleucum [3] 235 Anaphatol G. affine, G. adnatum [38,41] 236 7-O-(β-D-glucopyranosyl)-5-hydroxyisobenzofuran-1(3H)-one G. affine, G. adnatum [38,41] 237 4-(3',4'-dimethoxyphenyl)-3-methyl-butyl-3-ene-2-one G. affine, G.adnatum [38] 238 Desmethylyangonine-4'-glucopyranoside G. affine [38] 239 3-(4'-formylphenoxy)-4-methoxybenzaldehyde G. affine [38] 240 3-Hydroxydihydrobenzofuranose G. polycaulon [55] 241 Gnaphaliol 9-O-β-D-glucopyranoside G. polycaulon [55] 242 5,7-dihydroxyl-isobenzofuran-1(3H)-one G. affine, G. adnatum [41] 243 1-Hexacosanol G. affine [38] 244 Gnaohaliin C G. hypoleucum [3] 245 Benzeneacetaldehyde G. affine [48] 246 1-Tetratriacontanol G. affine [50] 247 Adenosine G. polycaulon [5] 248 4-hydroxyacetophenone G. affine [56] 249 Diethyl phthalate G. affine [38] 250 Diisobutyl phthalate G. pensylvanicum [36] 251 Dimethyl phthalate G. japonicum [46] 252 9,16-dixo-10,12,14-octadeca-trienoic acid G. affine [56] 253 N-hexacosanic acid G. affine [5] 254 Myristicin aldehyde G. affine, G. japonicum [46] 255 N-butyl-isobutyl terephthalate G. adnatum, G. affine [41,48] 256 1-Palmitoyl-rac-glycerol G. affine [50] 257 4'-hydroxydehydrokawain G. affine [38] Flavonoids
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Flavonoids are very common compounds in the genus Gnaphalium. Several studies have described flavonoids as a chemical index for the quality study of the herbs in Gnaphalium, even though they are not included in the Chinese Pharmacopoeia. Nevertheless, the flavonoid content in Gnaphalium is not high and varies significantly in different regions[36,37].
To date, over 100 flavonoids have been authenticated in genus Gnaphalium, which are mainly classified as flavonol, dihydroflavone, chalcone, and others. In flavonol, quercetin is the most significant aglycone, while luteolin and apigenin are the main skeletons in other flavonoids. Among the flavone glycosides in Gnaphalium, glucose is the main substituted group, which are mostly located in C-7 of flavonoids, except for C-3-substituted glucose in isorhamnetin-3-O-β-D-galactopyranoside (47), patuletin-3-O-β-D–glucopyranoside (48), quercetin-3-O-β-D-galactopyranoside (57), kaempferol-3-O-β-D-glucopyranoside (61), 3,5,7,4'-tetrahydroxy-3'-methoxyflavonoid-3-O-β-D-glucopyranoside (72), and 3,5,7,3',4'-pentahydroxy-6-methoxyflavonoid-3-O-β-D-glucopyranoside (73). Interestingly, another type of flavone glycosides, including quercetin-4'-O-β-D-(6''-E-caffeoyl)-glucopyranoside (46), apigenin-7-O-β-D-(6''-E-caffeoyl)-glucopyranoside (40), apigenin-4'-O-β-D-(6''-E-caffeoyl)-glucopyranoside (1), luteolin-4'-O-β-D-(6''-E-caffeoyl)-glucopyranoside (25), 5,7,3',4'-Tetrahydroxy-6-methoxyflavonoid-7-O-β-D-(6''-E-caffeoyl)-glucopyranoside (26), and naringenin-7-O-β-D-(6''-E-caffeoyl)-glucopyranoside (97), were isolated from G. affine, which contain an E-caffeoyl group in the flavone glycosides[57]. The information of the aforementioned flavonoids are presented in Figs 2−4 and Table 2, respectively.
Terpenoids
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Terpenes and terpenoids are very common natural products in the world, and over 22,000 chemicals have been identified from various plants[58]. Because of the basic five-carbon isoprene units in terpenes and terpenoids, they were divided into monoterpenoids, sesquiterpenes, diterpenoids, and triterpenoids with distinct functional groups[59,60]. Due to its diverse structures, several activities, such as anti-inflammatory, antiparasitic, antioxidant, anticancer, antiviral, and antimicrobial properties, have been reported[61]. In this review, 50 terpenes and terpenoids were identified in genus Gnaphalium (Figs 5−8, Table 2). Here, we will focus on these compounds and provide an overview of terpenes and terpenoids in genus Gnaphalium.
Triterpenoids
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Triterpenoids usually contain six five-carbon isoprene units. Normally, these units can be connected into different carbon ring and formed different types of triterpenoids. The major triterpenoids (105–120) isolated from genus Gnaphalium mainly use amyrin and ursolic acid as structural skeletons, and most of them are distributed in G. affine, except for squalene in G. gaudichaudianum. Among them, eight ursane triterpenes (109–116) are the most abundant, followed by four oleanane triterpenes (105–108). Also, three lupane triterpenes (117–119) and one chain triterpene (120) identified in G. affine. All information, including names, structures and source plants of triterpenoids, are listed in Table 2 and Fig. 5.
Diterpenoids
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Up to now, 37 diterpenoids are identified in genus Gnaphalium, and most of them possess (–)-pimara-8(14), 15-diene and (–) kaurene as chemical skeletons. In total, 22 kaurane diterpenes (132–147, 151–156), nine pimarane diterpenes (121–127, 148, 140), four labane diterpenes (128–131) were identified. In addition, there is one rare diterpene (157), which was a 15-hydroxy substituted wedeliaseccokaurenolide, from G. undulatum. The structures, names and source plants of diterpenes in genus Gnaphalium are presented in Fig. 6 and Table 2. By comparing the distribution of different compounds in genus Gnaphalium, it is found that diterpenes are the main component of G. gaudichaudianum, which can be regarded as a marker of G. gaudichaudianum to distinguish from other species.
Sesquiterpenoids
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A total of 20 sesquiterpenoids were isolated from genus Gnaphalium. Among them, 185 and 186 are isolated from G. oligandrum, while 170, 172, 176, and 177 are from G. japonicum. The specific information, including names and source plants of these compounds, are listed in Table 2.
Monoterpenoids
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Five monoterpenoids were identified from G. affine (178–182).
Phenolic acids
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Phenolic acids are normally considered as antioxidants because of the presence of phenol moiety and the ability to induce endogenous protective enzymes[62]. Also, phenolic acids have demonstrated anti-diabetic potential by inhibiting alpha-glucosidase and alpha-amylase, converting carbohydrates into glucose[63]. Furthermore, compared to methyl ester and butyl ester, the inhibitory effect of phenolic acid on microbial growth has been extensively investigated[64]. In genus Gnaphalium, 27 phenolic acids are isolated and identified, most of them are from G. affine. Additionally, caffeoyl substituted quinic acid is a special type of phenolic acids, in which quinic acid and caffeioyl groups are connected via the ester bond (Fig. 9, Table 2).
Steroids and sterols
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Sterol compounds are structurally composed of four-cyclic compounds with a cyclopentanoperophenanthrene nucleus[65]. However, only seven steroids have been authenticated in the genus Gnaphalium. Among them, β-sitosterol (212) was confirmed to exist in G. affine, G. hypoleucum, G. inornatum, G. pellitum, G. oxyphyllum, G. liebmannii, and G. viscosum. Among the species, all the steroids were identified from G. affine. One glycosides, β-daucosterin (210), was isolated from G.affine, G.adnatum, and G.hypoleucum[38].
Alkaloids
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Alkaloid compounds typically contain nitrogen atoms in their structures[66]. Currently, seven alkaloid (217–223) compounds have been found in the genus Gnaphalium.
Others
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In addition to the previously reported compounds, other types of compounds, including sterols, amino acids, tannins, polysaccharides, etc., have also been isolated from genus Gnaphalium[48] (Fig. 12, Table 2) .
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Data sharing not applicable to this article.
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About this article
Cite this article
Wang X, Liu D, Xiong L, Dunzhu B, Zhang L, et al. 2024. Ethnopharmacology, phytochemistry, bioactivities and quality control of the Gnaphalium genus: an updated review. Medicinal Plant Biology 3: e005 doi: 10.48130/mpb-0024-0003
Ethnopharmacology, phytochemistry, bioactivities and quality control of the Gnaphalium genus: an updated review
- Received: 17 October 2023
- Revised: 23 December 2023
- Accepted: 08 January 2024
- Published online: 19 March 2024
Abstract: The genus Gnaphalium (Asteraceae) is distributed across most regions of the world. Some of them are not only used as a food source, but has also been used for the treatment of various diseases including pain, rheumatism, chronic pharyngitis and arthritis in China since ancient times. In this review, we would like to summarize previous research on genus Gnaphalium, including traditional uses, phytochemistry, bioactivities and quality control. The data presented here on genus Gnaphalium was generated based on various scientific research databases, including SciFinder, PubMed, ScienceDirect, Wiley library, Web of Science, and CNKI. Analysis of these findings showed that plants in genus Gnaphalium have a capital power in various therapeutic uses, including pulmonary protection, antimicrobial activity, antioxidant activity, anti-inflammatory and anti-complementary activities, and antidiabetic effect. Consistent with this, the chemicals from the plant extracts revealed its richness in various chemicals, including flavonoids, phenolic acids, terpenoids, sterols, and others. In spite of its wide applicable value worldwide, the quality control of genus Gnaphalium is still based on local standards. Thus, we argue that a national standard is required for genus Gnaphalium in China, to validate its bioactivity and future clinical trials rigorously.
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Key words:
- Gnaphalium /
- Morphology /
- Phytochemistry /
- Ethnopharmacology /
- Pharmacological activities