The ocotillol (OCT)-type saponins have been known as a tetracyclic triterpenoid, possessing five-or sixmembered epoxy ring in the side chain. Interestingly, this type saponin was mostly found in Panax vietnamensis HA et GRUSHV., Araliaceae (VG), hence making VG unique from the other Panax spp. Five OCT-type saponins, majonoside R2, vina-ginsenoside R2, majonoside R1, pseudoginsenoside RT4, vina-ginsenoside R11, together with three protopanaxadiol (PPD)-type saponins and four protopanaxatriol (PPT)-type saponins from VG were evaluated for their antimelanogenic activity. All of isolates were found to be active. More importantly, the five OCT-type saponins inhibited melanin production in B16-F10 mouse melanoma cells, without showing any cytotoxicity. Besides ginsenoside Rd and ginsenoside Rg3 in PPD and notoginsenoside R1 in PPT-type saponins, majonoside R2 was the most potent melanogenesis inhibitory activity in OCT-type saponins. In this article, we highlighted antimelanogenic activity of OCT-type saponins and potential structure-activity relationship (SAR) of ginsenosides. Our results suggested that OCT-type saponins could be used as a depigmentation agent.

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A new menthane‐type monoterpene, alpigalanol (1), together with four known terpenes (2–5) were isolated from the ethyl acetate soluble fraction of the 70 % ethanol extract of the Alpinia galanga rhizomes. The structure of 1 was determined by spectroscopic analyses, including 1D‐ and 2D‐NMR. The extract of the A. galanga rhizomes and all isolated compounds (1–5) possessed Vpr inhibitory activities against the TREx‐HeLa‐Vpr cells at a concentration of 1.25 μM without showing any cytotoxicity.

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In the search of cytotoxic dihydrochalcones, this investigation led to the isolation of seven compounds (1-7) from Eriosema glomeratum and the preparation of eight derivatives (8-15). The cytotoxicity of samples was evaluated against lung (A549), breast (MCF-7), and cervical (HeLa) human cancer cells. The CH2Cl2/MeOH extract of the aerial part had strong cytotoxicity against all cells [IC50 11.2 (MCF-7), 8.4 (HeLa) and 13.1 (A549) 𝜇g/mL]. A strong activity was also displayed by the n-hexane fraction on MCF-7 (IC50 11.2 𝜇g/mL). The precursor 3 and the derivative 8 were specifically found as strong cytotoxic agents toward MCF-7 (7.6 𝜇M) and