Octanorcucurbitane and Cucurbitane Triterpenoids from the Tubers of Hemsleya endecaphylla with HIV-1 Inhibitory Activity

Abstract

Two new cucurbitacins, endecaphyllacins A (1) and B (2), together with six known analogues (3-8), were isolated from the tubers of Hemsleya endecaphylla. The structures of 1 and 2 were elucidated by NMR and MS spectroscopic analysis. The relative stereochemistry of 1 was determined by single-crystal X-ray diffraction. Compound 4 (cucurbitacin B) showed potent anti-HIV-1 in C8166 cells (EC=0.09 microg/mL) with a selectivity index of 16.7.

Plant-derived triterpenoids and analogues as antitumor and anti-HIV agents

“…234 These two compounds, together with three known cucurbitane analogues including 99, 100 , and cucurbitacin I ( 233 ), were evaluated for their ability to prevent the cytopathic effects of HIV-1 in C8166 cells. Although compounds 231 and 232 showed only moderate anti-HIV activity (EC 50 : 88.27 and 33.70 µM), 99, 100 , and 233 showed significant potency (EC 50 : 0.16, 0.23, and 1.36 µM, respectively) in this assay.…”

“…Although compounds 231 and 232 showed only moderate anti-HIV activity (EC 50 : 88.27 and 33.70 µM), 99, 100 , and 233 showed significant potency (EC 50 : 0.16, 0.23, and 1.36 µM, respectively) in this assay. 234 The high activity of 99, 100 , and 233 may be due to the presence of the C-17 functional side chain. However, because 99 is the first reported common cucurbitane analogue with potent antiviral activity, repeated evaluation may be necessary to confirm the compound’s potency.…”

Anti-HIV activity of natural triterpenoids and hemisynthetic derivatives 2004–2009

“…The hemlecins had no effect on viral protease and reverse transcriptase (Tian et al 2008 Two new octanorcucurbitacins and six previously described cucurbitacins, isolated from the tubers of Hemsleya endecaphylla C. Y. Wu, were tested for the inhibition of syncytia formation in HIV-1-infected C8166 cells. All compounds were at least moderately active, but cucurbitacin B showed very potent anti-HIV-1 activity (EC 50 = 0.09 lg/ml) with a selectivity index of 16.7 and the somewhat less potent 23, 24-dihydrocucurbitacin D and cucurbitacin I (EC 50 = 0.13 and 0.70 lg/ml, respectively) were more selective (SI = 20.6 and 50.0, respectively) (Chen et al 2008a).…”

Two new penterpenoid saponins and a new diterpenoid glycoside from Hemsleya chinensis

“…A number of cucurbitane compounds, including the famous hemslecins A and B, were isolated from this genus. Isolated compounds from Hemsleya species have been reported to demonstrate bioactivities, such as anti-inflammatory (Jayaprakasam et al, 2003), cytotoxic (Chen et al, 2014;Xu et al, 2014), anti-HIV (Chen et al, 2008), anti-HBV (Guo et al, 2013), anti-feedant activities (Lang et al, 2013). Interestingly, scandenoside R6 isolated from rhizomes of Hemsleya panacis-scandens tasted sweet while other cucurbitane glycosides tasted bitter or were tasteless (Kasai et al, 1988).…”