Phytochemical Investigation on the Chemical Constituents of Caralluma flava

Abstract

The research work embodied in this thesis deals with the isolation of chemical constituents from the Omani plant named Caralluma flava (N.E.Br) Meve & Liede along with the spectral characterization, biological activities and computational studies. Crude crystals (CR) obtained from the squeezed sap of succulent C. flava showed significant anticancer activity against MDA-MB-231 breast cancer cells and provided nine new pregnane glycosides namely Desmiflavaside A (1), Desmiflavaside B (2), Desmiflavaside C (3), Desmiflavaside D (4), Nizwaside (5), Desflavaside A (6), Desflavaside B (7), Desflavaside C (8) and Desflavaside D (9). The structures of these isolates were elucidated through spectral analysis using UV, IR, HRSEIMS, NMR and by comparing with literature reports. Treatment of MDA-MB-231 breast cancer and SKOV-3 ovarian cancer cells with compounds 3-5 demonstrated a prominent reduction in the viability of both types of cancer cells. Furthermore, 3-5 were also tested for their effect on normal breast epithelial cells (MCF-10-2A) which displayed no significant cytotoxicity on normal cells. The molecular docking studies of 3-5 revealed that these molecules have a good potential to bind with the target protein tyrosine phosphatase. The methanolic extract (ME) of squeezed residual plant and its different fractions also showed good anticancer activity against MDA-MB-231 cells. Different fractions of ME, CR and compounds (1-5) were additionally evaluated for enzyme inhibition (urease, acetylcholinesterase and α-glucosidase) and DPPH antioxidant activities which displayed no remarkable results. The research work embodied in this dissertation has resulted four publications as mentioned in the end of the thesis.