Biologically Active Secondary Metabolites from Asphodelus Microcarpus

Abstract

Bioassay guided fractionation of the ethanolic extract of Asphodelus microcarpus Salzm.et Vivi (Asphodelaceae) resulted in the isolation of one new metabolite, 1,6-dimethoxy-3-methyl-2-naphthoic acid (1) as well as nine known compounds: asphodelin (2), chrysophanol (3), 8-methoxychrysophanol (4), emodin (5), 2-acetyl-1,8-dimethoxy-3-methylnaphthalene (6), 10-(chrysophanol-7′-yl)-10-hydroxychrysophanol-9-anthrone (7), aloesaponol-III-8-methyl ether (8), ramosin (9) and aestivin (10). The compounds were identified by 1D and 2D NMR and HRESIMS. Compounds 3, 6 and 10 were isolated for the first time from this species. Compounds 3 and 4 showed moderate to weak antileishmanial activity with IC 50 values of 14.3 and 35.1 µg/mL, respectively. Compound 4 exhibited moderate antifungal activity against Cryptococcus neoformans with an IC 50 value of 15.0 µg/mL, while compounds 5, 7 and 10 showed good to potent activity against methicillin resistant Staphylococcus aureus (MRSA) with IC 50 values of 6.6, 9.4 µg/mL and 1.4 µg/mL respectively. Compounds 5, 8 and 9 displayed good activity against S. aureus with IC 50 values of 3.2, 7.3 and 8.5 µg/mL, respectively. Compounds 7 and 9 exhibited a potent cytotoxic activity against leukemia LH60 and K562 cell lines. Compound 10 showed potent antimalarial activities against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum with IC 50 values in the range of 0.8-0.7 µg/mL without showing any cytotoxicity to mammalian cells.

Asphodosides A-E, anti-MRSA metabolites from Asphodelus microcarpus

“…The 1 H and 13 C NMR spectroscopic patterns of the other half of the molecule were similar to compound 1. The 13 C NMR spectroscopic data of the sugar moiety of 5 (Table 1) was also superimposed with those reported for d -(+) glucose (Ghoneim et al, 2013). Accordingly compound 5 was assigned as chrysalodin-10-oxanthrone-(10′ S )- β - d -glucopyranoside (Asphodoside E).…”

“…This class of compounds contains derivatives that consist of the basic structure of a 9, 10-anthraquinone moiety (Bajaj and Ishimaru, 1999). In continuation of efforts to search for new antimicrobial metabolites from A. microcarpus using biological activity guided fractionation, several anthraquinones showed activity against both methicillin resistant Staphylococcus aureus (MRSA) and S. aureus (Ghoneim et al, 2014, 2013), and five new compounds (1–5) were isolated and their antimicrobial activities were evaluated Fig. 1.…”

A Comprehensive Review on the Medicinal Plants from the Genus Asphodelus

“…In particular, A. aestivus , A. fistulosus and A. microcarpus were reported to be used in dermatomucosal infections in various countries including Cyprus, Egypt, Libya, Palestine, and Spain [16,17,18,19,20]. A. microcarpus , A. ramosus and A. tenuifolius were generally indicted as anti-inflammatory agents specifically for the treatment of psoriasis, eczema, and rheumatism [21,22,23,24,25,26,27,28]. A. aestivus and A. tenuifolius are also used for ulcer treatment in Turkey, India, and Pakistan [26,27,28,29].…”

“…Although the leaf seems to have stronger antimicrobial activity in comparison with roots, in general, both exhibit weak or no antimicrobial/antifungal activity [20,48,49,70]; however, compounds isolated from root tubers extracts showed potent activity such as asphodelin A against S. aureus (MIC = 16 µg/mL), Escherichia coli (MIC = 4 µg/mL), Pseudomonas aeruginosa (MIC = 8 µg/mL), Candida albicans (MIC = 64 µg/mL) [19] and Botrytis cinerea (MIC = 128 µg/mL) and asphodoside B against MRSA (IC 50 = 1.62 μg/mL) [51]. Other isolated compounds from root extracts showed different biological activity; for instance, ramosin showed potent cytotoxic activity against leukemia cell lines [21], aestivin showed potent antimalarial activity against chloroquine-sensitive and resistant strains of Plasmodium falciparum with IC 50 of 0.8–0.7 μg/mL [21] and 3,4-dihydroxy-methyl benzoate exhibited anti-parasitic activity against Leishmania donovani promastigotes with IC 50 of 33.2 µg/mL [54]. …”

Isolation and characterization of new secondary metabolites from Asphodelus microcarpus

“…A. microcarpus is used to treat ectodermal parasites, jaundice, and psoriasis, and is also used by Bedouins as an antimicrobial agent (Tackholm, 1974). A literature survey revealed that lipids, sterols, triterpenes, anthraquinones, and arylcoumarins have been isolated from A. microcarpus (El-Seedi, 2007; Ghoneim et al , 2013). Anthraquinones and pre-anthraquinones are considered to be important chemotaxonomic markers for plants in the family Asphodelaceae (Van et al , 1995).…”