Isoshinanolone

Bioorg Med Chem Lett. 2010 May 1;20(9):2974-7.

Bioactivity-guided isolation of mosquitocidal constituents from the rhizomes of Plumbago capensis Thunb.[Pubmed: 20347303 ]

METHODS AND RESULTS:
A bioassay-guided fractionation and chemical examination of chloroform extract of Plumbago capensis roots resulted in isolation and characterization of two new napthaquinone derivatives (4, 8) along with six known compounds (1-3, 5-7). Their structures were determined on the basis of extensive spectroscopic (IR, MS, 1D and 2D NMR) data analysis and by comparison with the literature data. All the compounds were tested for their mosquito larvicidal activity against fourth instar larvae of Aedes aegypti, and compared with that of rotenone.
CONCLUSIONS:
Among the tested compounds, Isoshinanolone (3) and plumbagin (1) showed excellent toxicity with LC(50) values of 1.26 and 5.43 microg/mL. New compound (8) displayed moderate toxicity against the tested mosquito species.

Diseases. 2016 Jan 15;4(1). pii: E3.

Phytoconstituents with Radical Scavenging and Cytotoxic Activities from Diospyros shimbaensis.[Pubmed: 28933383 ]

As part of our search for natural products having antioxidant and anticancer properties, the phytochemical investigation of Diospyros shimbaensis (Ebenaceae), a plant belonging to a genus widely used in East African traditional medicine, was carried out.
METHODS AND RESULTS:
From its stem and root barks the new naphthoquinone 8,8'-oxo-biplumbagin (1) was isolated along with the known tetralones trans-Isoshinanolone (2) and cis-Isoshinanolone (3), and the naphthoquinones plumbagin (4) and 3,3'-biplumbagin (5). Compounds 2, 4, and 5 showed cytotoxicity (IC50 520-82.1 μM) against MDA-MB-231 breast cancer cells. Moderate to low cytotoxicity was observed for the hexane, dichloromethane, and methanol extracts of the root bark (IC50 16.1, 29.7 and > 100 μg/mL, respectively), and for the methanol extract of the stem bark (IC50 59.6 μg/mL).
CONCLUSIONS:
The radical scavenging activity of the isolated constituents (1-5) was evaluated on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The applicability of the crude extracts and of the isolated constituents for controlling degenerative diseases is discussed.