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

Abstract

Bioassay guided fractionation of the ethanolic extract of Asphodelus microcarpus Salzm. et Viv. (Xanthorrhoeaceae or Asphodelaceae) resulted in isolation of five compounds identified as asphodosides A-E (1–5). Compounds 2–4 showed activity against methicillin resistant Staphylococcus aureus (MRSA) with IC50 values of 1.62, 7.0 and 9.0 μg/mL, respectively. They also exhibited activity against Staphylococcus aureus (non-MRSA) with IC50 values of 1.0, 3.4 and 2.2 μg/mL, respectively. The structure elucidation of isolated metabolites was carried out using spectroscopic data (1D and 2D NMR), optical rotation and both experimental and calculated electronic circular dichroism (ECD).

Tyrosinase inhibition and antioxidant properties of Asphodelus microcarpus extracts

“…Various biological activities have been reported for A. microcarpus , [12, 13]. Phytochemical studies on A. microcarpus revealed the presence of lipids, carbohydrates, sterols, anthraquinones and arylcoumarins [13, 14].…”

“…Various biological activities have been reported for A. microcarpus , [12, 13]. Phytochemical studies on A. microcarpus revealed the presence of lipids, carbohydrates, sterols, anthraquinones and arylcoumarins [13, 14]. It is well known that the last two compounds have tyrosinase inhibitory activity [15–17] and plant extracts with antimelanogenic activity typically possess polyphenols such as flavonoids, which are usually the factors responsible for the activities in plant extracts [18].…”

A Comprehensive Review on the Medicinal Plants from the Genus Asphodelus

“…The ethanol extracts of leaves demonstrated strong antiviral activity against Ebola virus (EBOV) in the concentration of 0.1–0.3 µg/mL [49]. 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].…”

Recent Advances on anti-MRSA Natural Products Derived from Plants

“…[28] Anthraquinones Anthraquinones are a class of natural compounds that consist of several hundred compounds that differ in the nature .0 and 9.0 μg/mL, respectively. [29] Emodin (53), purified from the extract of Hypericum riparium leaves also showed significant antimicrobial potential (IC50 = 11.71 μg/mL) against MRSA. Further research revealed that compound 53 could damage the integrity of cell wall, leading to loss of intracellular components ( Figure 5).…”