Studies On The Chemical Constituents And Bioactivities Of Akebiae Quinata

The fruits of Akebia quinata (Thunb.) Decne. is one of the sources of Chinesemedicine "Yuzhizi", which is used as an diuretic, anti-tumor, bacteriostasic agent in clinic.Previous chemical investigations revealed that the plants of the genus Akebia possessedrich saponins. In order to improve the exploiting and using of the Akebia, theinvestigations on the bioactive constituents of Akebia quinata have been carried out.Using various chromatographic methods, 40 compounds including 22 triterpenesaponins have been isolated from the fruits of Akebia quinata. On the basis of theirphysicochemical and spectroscopic evidences, their structures were elucidated as follows:3-O-α-L-arabinopyranoside hederagenin (B-1), 3-O-β-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl gypsogenin (B-2), 3-O-α -L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosyl gypsogenin (B-3), 3-O-α -L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosyl oleanolic acid (Prosapogenin, B-4), 3-O-β-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl oleanolic acid (B-5), 3-O-β-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl hederagenin (Saponins B, B-6), 3-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl hederagenin (B-7), 3-O-β -D-xylopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α -L -arabinopyranosyl hederagenin (B-8), 3-O-α-L-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl-28-O-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside hederagenin (Dipsacoside B, B-9), 3-O-β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl oleanolic acid (B-10), 3-O-β-D-glucopyranosyl(1 → 3)-α -L-rhamnopyranosyl-(1 → 2)-α -L -arabinopyranosylhederagenin (B-11), 3-O-([β-D-glucopyranosyl(1→4)]-[α-L-rhamnopyranosyl-(1→2)]-α -L –arabinopyranosyl) hederagenin (Pulsatilla saponin D, B-12), 3-α -L-arabinopyranosyl-28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl hederagenin(Saponin D, B-13), 3-O-β-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl-28-O-β-D-glucopyranosyl-(1 → 6)-β -D-glucopyranosyl gypsogenin (B-14), 3-O-β -D-xylopyranosyl-(1 → 2)-α -L-arabinopyranosyl-28-O-β -D-glucopyranosyl-(1→ 6)-β-D-glucopyranosyl oleanolic acid (B-15), 3-O-β -D-xylopyranosyl -(1 → 2)-α-L-arabinopyranosyl-28-O-β -D-glucopyranosyl-(1 → 6)-β -D-glucopyranosylhederagenin (Saponin E, B-16), 3-O-α -L-rhamnopyranosyl(1 → 2)-α-L-arabinopyranosyl-28-O-β-D-glucopyranosyl(1→6)-β-D-glucopyr-anoside oleanolicacid (B-21), 3-O-α-L-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside hederageninKalopanaxsaponins B (Kalopanaxsaponins B, B-22), 3-O-β-D-glucopyranosyl (1→2)-α-L-arabinopyranosyl-28-O-α-L-rhamnopyranosyl (1→4)-β-D-glucopyranosyl (1→6)-β-D-glucopyranoside oleanolic acid (B-23), 3-O-β -D-xylopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1→2)-α-L– arabinopy-ranosyl-28-O-α-L-rhamnopyranosyl(1→4)-β -D-glucopyranosyl(1 → 6)-β -D-glucopyranoside oleanolic acid (B-24), 3-O-β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L -arabinopyranosyl-28-O-α-L-rhamnopyranosyl(1 → 4)-β -D-glucopyranosyl (1 → 6)-β -D-glucopyranosidehederagenin(Patrinia saponin H3, B-25), 3-O-α -L-rhamnopyranosyl(1 → 2)-[ β -D-glucopyranosyl(1→4)]-α-L-arabinopyranosyl-28-O-α-L-rhamnopy-ranosyl-(1→4)-β-D-glucopyranosyl(1→6)-β-D-glucopyranoside hederagenin (Hederacholichiside F, B-26).3 coumarins: Esculetin (E-10), Hymexelsin (B-19), Scopolin (B-20);2 iridoids:geniposidic acid (B-17), 10-O-acetylgeniposidic acid (B-18);13 other compounds:15-nonacosanol (E-1), palmitic acid (E-2), stigmasterol (E-3), β -sitosterol (E-4),p-hydroxybenzoic acid (E-5), Vomifoliol (E-6), p-hydroxyphenylethyl alcohol (E-7),Oleanolic acid (E-8), (2S,3S,4S)-2-Methyl-tetrahydrofuran-3,4-diol (E-9), protocatechuicacid (E-11), caffeic acid (E-12), β -daucosterol (E-13), Stigmasterol-3-O-β-D-glucopyranoside (E-14). Among these compounds, B-2,B-3 and B-14 are newcompounds, compounds B-4,B-5,B-9,B-10,B-11,B-12,B-21,B-23,B-24,B-26 ,E-1,E-2,E-5,E-6,E-7,E-9,E-10,E-11,E-12 are isolated from this genus for thefirst time.On the basis of chemical investigation, the bioactivities of the extracts and somepurified compounds have been tested. The group with high dosage of n-butanol extractsshowed significance inhibitory on Candida albicans and Cryptococcus. The group withhigh dosage of ethyl acetate extracts and 95% ethanol extracts showed significanceinhibitory on Candida albicans and Cryptococcus. The group with low dosage of totalsaponins and compound B-11 (1.25 g/kg) indicated outstanding diuretic activity. Moreover,compounds B-16 showed significance inhibitory on COX-2. All the compounds tested didnot indicate anti-tumor activities.