PHYTOCHEMICAL STUDIES ON H. EICHWALDI AND RELATED SPECIES

Abstract

This Ph.D thesis deals with the phytochemical studies on two species of the genus Heliotropium of Pakistani origin. The thesis is divided in to two parts: Section A deals with the phytochemical studies on Heliotropium eichwaldi that have led to the isolation of a novel compound Furo furan lactone [(4a,6b-dihydroxy-5-(hydroxymethyl)-2a-isopropyl-2-methylhexahydro- 4H-1,3,6-trioxacyclopenta[cd]pentalen-4-one)] 1. The structure elucidation of compound 5 was done by spectroscopic means and confirmed by X-ray crystallographic technique [Firdous S. et al., 2012 a]. In addition to that three known compounds, Heliotrine 4, β-Sitosterol 3-O- β-D-glucopyranoside 5 and β-Sitosterol 6 have also been isolated and characterized from this species. Section B of the thesis describes work on a related species Heliotropium ophioglossum. The phytochemical investigation on this plant resulted in the isolation and characterization of two new compounds Ophiamide-A (2S,3S,4R,6E,2̍R)-2-[2'-hydroxypentacosanoylamino]-octadec-6-ene-1,3,4-triol 42 and Ophiamide-B 1-O-β-D-glucopyranosyl-(2S,3S,4R,6E,2̍R)-2-[(2'-hydroxypentacosanoylamino]-octadec-6-ene-1,3,4-triol 43. These two new compounds exhibited potent urease inhibitory activity [Firdous S. et al., 2012 b]. In addition to this eight known compounds have also been isolated and identified for the first time from this species. The known compounds isolated from H. ophioglossum are 2'(4''-Hydroxyphenyl)-ethyl Lignocerate 44, Glycerol Monopalmitate 45, Methyl 2,4-Dihydroxy Cinnamate 46, 4-Hydroxycinnamic acid 47, 4-Hydroxybenzoic acid 48, 1-Octacosanol 49, β-Sitosterol 3-O- β-D-glucopyranoside 5 and β-Sitosterol 6. The structure elucidation of all compounds involved modern spectroscopic techniques such as MS, 1H and 13C-NMR, IR and UV.