Journal of Medicinal Plant and Herbal Therapy Research
ISSN: 2053-1826
Vol. 10(1), pp. 1-9, March 2023
doi.org/10.33500/jmphtr.2023.10.001

Phytochemical analysis, kill kinetics and in vivo toxicity evaluation of crude methanolic extract of Senna alata (Fabaceae) (L.) Roxb. (Bark)

Oluwatobi O. B.¹, Igbokwe C. O.²*, Williams T.³, Famojuro O. B.⁴, and Makinde S. O.²

¹Department of Microbiology, Federal University of Agriculture, Abeokuta, Nigeria.
²Department of Pharmaceutical Microbiology, University of Ibadan, Nigeria.
³Department of Pharmaceutical Microbiology, Afe-Babalola University, Ekiti State, Nigeria.
⁴Department of Pharmaceutical Microbiology, Olabisi Onabanjo University, Sagamu, Ogun State Nigeria.

*To whom correspondence should be addressed. E-mail: chrisigbokwe@gmail.com.

Received 09 December, 2022; Received in revised form 19 January, 2023; Accepted 24 January, 2023.

Abstract

Keywords:
Sena alata, Phytochemicals, antibiotics, Kill-kinetics, Toxicity, Haematological parameters.

The rapid emergence of anti-microbial resistance by pathogenic agents, has been a continuous challenge, which has called for the development of an alternative therapeutic agent. Senna alata, as a medicinal plant, has been extensively exploited in meeting the healthcare needs of the indigenous people in many parts of the world. This study was designed to analyze the phytochemical composition, determine the kill kinetics, and evaluate the toxicity potentials of Senna alata (leaf, flower, and bark), a promising plant source for novel antibiotics. Dried powdered samples of S. alata leaf, flower, and bark were extracted to obtain crude methanol extracts of each part. The extracts were analyzed for the presence of secondary metabolites. Based on the minimum inhibitory concentration (MIC) of the extract, the kill kinetics of the susceptible pathogens were determined at MIC, 2 x MIC, 4 x MIC, and 8 x MIC concentrations. The in vivo toxicity evaluation was carried out using Wistar rats, to determine the highest concentration of the extract that would kill half of the treated animals (LD₅₀). The animals were given various concentrations via oral gavage for 28 days for subacute toxicity, after which liver function and haematological parameters were analyzed for signs of toxicity. The phytochemical profile revealed the presence of glycosides, alkaloids, tannins, saponins, flavonoids, anthraquinones, volatile oils and phenol in all the plant parts, while carbohydrates were found only in the bark and leaf. The kill-kinetics showed a time- and concentration-dependent trend, when the log cfu/mL was plotted against time. The result of the acute toxicity gave an LD₅₀ > 6000 mg/kg body weight. The sub-acute toxicity evaluation on the Wistar rats revealed that the liver function parameters, such as alanine amino transferase (ALT), aspartate amino transferase (AST), and alkaline phosphatase (ALP) did not vary significantly (p<0.05) as well as the creatinine of the treated rats. Haematological parameters (white blood cells, red blood cells, and platelets) were also not affected. The results showed the potential of S. alata as a source of broad-spectrum antimicrobial compounds that can be administered without fear of toxicity or side effects.