Abstract:
This PhD thesis envisages the phytochemical and pharmacological studies of an
important member of Rhamnaceae family, Zizyphus oxyphylla Edgew. The main objective
behind this investigation was to authenticate the folkloric history of this plant. Some of the
folkloric uses of genus Zizyphus from the available literature include antidiabetic, hepatic
protective, antioxidant, and antiulcerinic, antibacterial and anticancer while specifically
Zizyphus oxyphylla is famous for its analgesic, antipyretic and hepatic protective uses.
Fractions of stem, leaves and roots of Z. oxyphylla were screened for phytochemical
constituents while fractions of stem and leaves were screened for pharmacological activities.
This scientific pursuit resulted in some significant findings. The phytochemical studies on Z.
oxyphylla resulted in isolation and structural elucidation of three new compounds. Two of the
new compounds were cyclopeptide alkaloids named Oxyphylline B (1) and Oxyphylline C
(2) while the third new compound was a flavone i.e. (+)-R, S Maackiain (3). Apart from these
new compounds four other compounds Oxyphylline D (4), Nummularine-C (5),
Nummularine-R (6), -Sitosterol (7) and Stigmasterol 3- O- -glucosides (8) were also
isolated. Amongst these known compounds only Nummularine-R (6) was previously isolated
from Z. oxyphylla while other known compounds were isolated for the first time from this
plant and thus new source. Oxyphylline B (1), Oxyphylline C (2) and Nummularine-R (6)
were isolated from the chloroform fraction of stem of Z. oxyphylla. From the
dichloromethane fraction of roots Oxyphylline D (4) and Nummularine-C (5) were isolated
while (+)-R, S Maackiain (3), -Sitosterol (7) and Stigmasterol 3- O- -glucoside (8) were
isolated from the ethyl acetate fraction of leaves of Z. oxyphylla.
Stem and leaves oils sub fractions, when analyzed by GC-MS, yielded fatty acids,
lipids, long chain hydrocarbons and long chain ketones. Some major compounds which were
yielded in high percentage were Heptacosane (10.0782 % in sample WO3), Tetracosane acid,
methyl ester (9.2234 % in sample WO2), Dotriacontane, 1-Hexacosene and 1-Eicosene
(6.4403, 6.6830 and 6.1095 respectively in sample WO5), 11decyl Tetracosane, (4.2749 % in
sample WO1), Azafirin (4.4609 % in sample WO1) and 9-octyl Hexacosane, (3.7489 % in
sample WO1). While other known compounds below were 3 % concentrations. Few of the
peaks in gas chromatogram and their respective mass spectral data remained unidentified.
As regards to pharmacological studies, some interesting and significant findings were
obtained. Crude extracts, fraction and some of the isolated compounds were investigated for
antibacterial, antifungal, toxicity tests (Brine shrimp bioassay, lemna bioassay, insecticidal),
in vitro anti-inflammatory activity and enzyme inhibition bioassays including urease and
carbonic anhydrase inhibition bioassays. Only ethyl acetate fraction of leaves showed
moderate antibacterial activity. Crude extract and n-hexane fraction of leaves and only n-
hexane fraction of stem exhibited 35 % inhibition of fungal growth. Maximum phytotoxic
activity was revealed by both stem and leaves at the highest concentration used. Crude extract
of leaves gave the highest inhibition (90 %) while chloroform was the most active fraction of
stem of Z. oxyphylla.
Neither of the extracts and subsequent fractions from stem or leaves were able to
produce an impression as active cytotoxic agent. n-hexane and ethyl acetate fraction of leaves
exhibited 40 % mortality against Callosobruchus analis. Two fractions of leaves (chloroform
and n-hexane) gave excellent anti inflammatory activity when screened for in vitro anti-
inflammatory activity. Polar fractions of stem showed the maximum urease inhibitory
activity. Ethyl acetate fraction of the stem gave maximum reading of 86.7 % ± 0.03, while
leaves showed low urease inhibitory activity. Stem and leaves of Z. oxyphylla exhibited low
to moderate carbonic anhydrase activity.
Oxyphylline B (1) showed comparatively better antibacterial activities against
Escherichia coli and Pseudomonas aeruginosa (MIC: 0.1 mg/mL). Oxyphylline C (2)
showed a lower antibacterial activity as compared to Oxyphylline B. Oxyphylline D (3)
showed its highest antibacterial activity against E. coli and it lowest antibacterial activity
against Shigella flexenari. Nummularine-C (5) and Nummularine-R (6) when compared we
found that Nummularine-C was more active than Nummularine-R in many cases.
Oxyphylline B (1) showed low activity against Candida albicans. While in the case of
Oxyphylline C (2) it was found that it was moderately active against three fungal strains i.e.
C. albicans, Micropspoum canis and Fusarium solani.
Nummularine-R (6) and Oxyphylline B (1) showed low inhibition of Jake bean
urease. Both of them gave readings of 35.73 and 34.24 % inhibition. Maximum urease
inhibitory activity was shown by Oxyphylline D (3). It inhibited the urease enzyme by 58.21
%. When IC50 ± SEM value was calculated it came out to be 420.11 ± 1.22 μM.
New compounds