Comparative analysis of Pavetta Crassips and Pavetta Schumanniana as ethnomedicines from Dedza and Mzimba in Malawi

Abstract

avetta crassipes and P. schumanniana are some of the neglected and underutilised, yet useful medicinal plants in Malawi. In regions where P. crassipes and P. schumanniana leaves are traditionally used for medicinal purposes, there is lack of scientific understanding regarding their therapeutic efficacy, chemical composition, and antimicrobial properties. The objective of the study was to compare ethno medicinal use, phytochemical composition and antimicrobial activity of P. crassipes and P. schumanniana plant leaves. The study was conducted in March, 2022. This study used both qualitative and quantitative methods. In ethno medicinal survey, simple random and snowball sampling procedures were used to select sites and respondents respectively. Data were analysed using SPSS version 20 and STATA version 16. Chi-square test was used to determine significant differences or associations in parameters of interest between the two plant species. For phytochemical analyses, qualitative chemical methods of analysis were used to study phytochemical compounds. For microbial effects, the diffusion disc method was used to assess antimicrobial activity of the leaf extracts against E coli and S. aureus. The zone of inhibition of P. crassipes and P. schumanniana aqueous leaf extract in mm were entered into STATA version 16, and thereafter were subjected to One Way Analysis of Variance (ANOVA). Some diseases that were reported to be managed by P. schumanniana and were common whilst others were specific to one plant species. P. schumanniana was commonly used to manage cough while P. crassipes was commonly used as libido enhancer. Phytochemical analysis revealed the presence of bioactive compounds in P. crassipes leaves which were steroids, tannins, anthocyanin and anthraquinones, while P. schumanniana leaves contained saponins, terpenoids/steroids, tannins and anthocyanins. Alkaloids and flavonoids were not detected in both plant species. The data showed a concentration dependent efficacy on E. coli while S. aureus was resistant to both species. The most effective concentration (100 µg/mL) of P. crassipes and P. schumanniana aqueous leaf extract recorded highest mean zone of inhibition of 8.10±0.89 mm (p = 0.915) and 7.73±0.67 mm (p = 0.999) for P. crassipes and P. schumanniana, respectively. This study validates the traditional uses of Pavetta schumanniana and Pavetta crassipes, highlights their potential as sources of antimicrobial agents, and provides a foundation for further research into their bioactive compounds.