Abstract :
Seasonal and geographical variations have impact on secondary plant metabolites in medicinal plants. In the
present study an attempt was made to evaluate the phytochemical variation and its effect on the medicinal properties
of Tribulus terrestris which was collected from two different seasons (Summer and winter) and from two different
geographical regions i.e. Rafha, and Riyadh, Saudi Arabia (hot desert climate) and Bangalore, India (tropical
savanna climate).The amount of Phenolic acids and flavonoids was evaluated by Folin ciocalteu method and
Aluminum chloride colorimetric method respectively. Anti-oxidant activity was carried out for all the extracts by the
DPPH method .The results revealed that the amount of phenolic acid and flavonoid was found to be higher i.e. 428
μgm and 295 μgm respectively in TT1-S which was in the sample collected during summer from the Rafha region.
To further investigate the best season of collection of samples in Rafha, HPLC analysis was carried out for TT1-S
and TT1 –W extracts using rutin and gallic acid as the standards; the amount of rutin and gallic acid was found to
be higher in TT1-S. Furthermore analgesic activity was carried out for these extracts and the sample collected
during summer exhibited significant activity when compared to the sample collected during winter. The results of
this study give evidence that the season and geographical variations bring about a change in the plant metabolites
which in turn affect the medicinal properties .From the results it is evident that the best season to collect the plant is
during summer in Rafha as the amount of phytoconstituents is found to be more during this season.
Keyword :
Tribulus terrestris, seasonal, geographical, phytoconstituents, medicinal properties