Effect of seasonal changes on the quantity of phytochemicals in the leaves of three medicinal plants from Limpopo province, South Africa

The study was carried out to investigate the effect of seasonal changes on the quantity of phytochemicals in leaves of three medicinal plants: Barleria dinteri, Grewia flava and Jatropha lagarinthoides, collected from Limpopo province in South Africa. Three medicinal plants were collected during different seasons of the year and phytochemicals were quantified on plant samples collected in each season. Alkaloids and tannins were in high amounts during colder seasons (autumn and winter) in all plants, whereas flavonoids were in high amounts during warmer seasons (spring and summer). In addition, saponins were in high amounts during warmer seasons in G. flava and J. lagarinthoides, while no significant seasonal difference was recorded in B. dinteri. Furthermore, simple phenols were in high amounts during autumn in G. flava, while in high amounts during summer in J. lagarinthoides with no significant difference amongst seasons in B. dinteri. The findings of the study indicate that seasonal changes affected the quantity of inherent phytochemicals in the leaves of three medicinal plants under current study in a phytochemical specific manner.     Key words: Barleria dinteri, Grewia flava, Jatropha lagarinthoides, phytochemicals, seasonal changes, quantitative