Study of Antimalarial Activity of Chemical Constituents from Diospyros quaesita

Abstract

Bioassay-directed fractionation led to the isolation of seven compounds from a sample of the dried leaves, twigs, and branches of Diospyros quaesita Thw. (Ebenaceae). One of the isolates, betulinic acid 3-caffeate (1), showed in vitro antimalarial activity against Plasmodium falciparum clones D(6) (chloroquine-sensitive) and W(2) (chloroquine-resistant) with IC(50) values of 1.40 and 0.98 microM, respectively. Evaluation of compound 1 in the human oral epidermoid (KB) cancer cell line revealed cytotoxicity at ED(50) of 4.0 microM. In an attempt to reduce the cytotoxicity of 1, the acetylated derivative 1a and betulinic acid (1b) were prepared. Of the seven isolates, diospyrosin (2) was determined to be a new neolignan. In addition to 1, other known compounds isolated in this study were pinoresinol, lariciresinol, N-benzoyl-L-phenylalaninol, scopoletin, and poriferast-5-en-3beta,7alpha-diol. The structure of 2 was elucidated based on spectroscopic data analysis including 1D- and 2D-NMR, and HR-ESI-MS.

Antimalarial activity of extract and norbergenin derivatives from the stem bark of Diospyros sanza‐minika A. Chevalier (Ebenaceae)

“…Although the plant is not traditionally known in Cameroon to treat malaria, the present study may provide some scientifi c basis on which traditional usage of Diospyros sanza-minika extracts could be encouraged. Several studies have indeed documented the antimalarial potency of crude extracts from the genus Diospyros as well as that of some of their antimalarial constituents (Likhitwitayawuid et al, 1999;Ma et al, 2008;Kantamreddi and Wright, 2008), which were generally found to be triterpenes such as betulinic acid 3-caffeate from Diospyros quaesita (Ma et al, 2008) and naphthoquinones such as diospyrin from Diospyros montana (Likhitwitayawuid et al, 1999). Bergenin, an isocoumarin previously isolated from Diospyros sanza-minika (Musgrave and Skoyles, 1974) was found to be inactive against P. falciparum and only weakly active against P. berghei (Silva et al, 2004).…”

“…Malaria is a major threat to global health with ca. 40% of the world's population being exposed to this parasite (Ma et al, 2008).…”

“…Genus Diospyros contains more than 350 species, some of which are known in traditional systems of medicines such as Ayurveda, the African folklore and Chinese medicine (Tangmouo et al, 2006;Chen et al, 2008). While no traditional medicinal uses have been described for Diospyros sanza-minika, extracts of some other Diospyros species showed signifi cant antimalarial potential (Likhitwitayawuid et al, 1999;Ma et al, 2008;Kantamreddi and Wright, 2008). Previous evaluations of the therapeutic potential of Diospyros sanza-minika were limited only to their antioxidant properties (Tangmouo et al, 2009).…”

Revisiting the linkage between ethnomedical use and development of new medicines: A novel plant collection strategy towards the discovery of anticancer agents

“…Although no bio-prospecting and isolation work from the Lao PDR has thus far proceeded to the stage of patent filing thereby meriting additional studies (unlike for Vietnam; Zhang et al, 2014Zhang et al, , 2017, through the VietnamLaos ICBG, six medicinal plant taxa from around the country have been evaluated through the compound isolation stage and have been found to contain mostly novel phytochemicals bearing anti-tuberculosis , anti-malarial (He et al, 2005(He et al, , 2006Libman et al, 2008;Ma et al, 2008); and cancer cell cytotoxicity activities (Zhang et al, 2004). With respect to anticancer bio-prospecting from the ICBG field work conducted from 1998 to 2012 in the Lao PDR, at least 34 species yielded 50 extracts with significant activity (IC 50 < 20 μg/ml) in one or more cancer cell lines of a six cell line panel, which notably led to the isolated compounds asparacoside and 3''-methoxy-nyasol (IC 50 > 4 μg/ml, < 10 μg/ml) from Asparagus cochinchinensis (Lour.)…”

Preparation of Derivatives of Betulinic Acid, Steviol and Isosteviol and Evaluation of Antitrypanosomal and Antimalarial Activities

“…6 Other studies have also reported the antimalarial potential of that compound and its derivatives. [7][8][9][10][11][12][13][14][15][16][17][18][19][20] A few tetracyclic diterpenes have also shown antimalarial properties. One example is a norpimaran lactone (1d, Figure 1) obtained from manool, 21 and another is kaurenoic acid (3a, Figure 3) described as weakly active.…”