Phytochemical screening and antimicrobial susceptibility testing of Eucalyptus dalrympleana’s leaf extracts from Namibia

Abstract

Eucalyptus dalrympleana plant is originally from Australia, and widely distributed throughout the world which it comprises of about 800 species of tall trees. The leaves and oil of E. dalrympleana are traditionally used by indigenous people as herbal remedy to relief respiratory ailments and feverish conditions such as asthma, bronchitis, coughs, diarrhoea and flu as well as for skin problems, like burns, ulcers, and wounds. Transformation of natural products from plants as herbal remedies, is a great inspiration on today’s researches. Five (5) crude extracts from the leaves of E. dalrympleana, were prepared using different solvents;hexane, dichloromethane (DCM), methanol (MeOH), water and a mixture of DCM: MeOH. Phytochemical screening on the plant extract revealed the presence of biochemical compounds such as saponins, alkaloids, phenolic, tannins, and flavonoids.  The crude extracts were further tested for antimicrobial activity against microbial strains such Klesbscilla Pneumonia, Staphylococcus aureus, Escherichia coli and Candida albicans, through disk diffusion method. A mixture of DCM: MeOH extract shows a great inhibition of all the aforementioned strains. Quantification of biochemical compounds reveals the presence of flavonoids as most abundantly in DCM: MeOH extract (40.8558g) and least in MeOH extract (27.0636g), followed by saponins which reported to be in low quantity in DCM: MeOH (2.4088g) and high quantity in MeOH (3.5750g). Alkaloids, tannins and phenolic compounds were present in small amounts as follow; in plant material (1.5258g), DCM: MeOH extract (0.03185g) and MeOH extract (0. 03027g). The main highlights of this article are their greater medicinal value of phytochemicals present, antimicrobial activity and antioxidant activity is due to the presence in of flavonoids in presents in Eucalyptus dalrympleana’s plant.

Keyword: Phytochemical screening; Alkaloids, flavonoid, Saponins, quantification, Anti-microbial