Phytochemical, antimicrobial and proximate analysis of <em>Costus spectabilis</em> grown in different soil types

Abstract

The search for medicinal plants with novel properties for therapeutical potentials is a continuum. The preliminary phytochemical analysis, antimicrobial properties and proximate contents of Costus spectabilis leaf and root harvested from different soil types were studied following standard protocols. The ethyl ethanoate extracts were assayed against six microbial cultures of Staphylococcus aureus (ATCC 29523), Pseudomonas aeruginosa (ATCC 27853), Bacillus subtilis (ATCC 6633), Aspergillus niger, Candida albicans, and Aspergillus clavatus using the agar well diffusion methods. The phytochemical analysis revealed the presence of alkaloids, saponin, phenol, flavonoids and anthraquinone in all samples at varying concentrations. Terpenes and phlobatannins were not observed in any extract. Phenolic compound was observed to have the highest quantity of 6.18±0.00 mg/g from the leaf extract of the plant grown in loamy soil. Tannin and flavonoids were only detected in very insignificant quantities. The extracts showed significant inhibitory potential against the bacterial strains. The highest zone of inhibition was recorded as 33.02±1.45 mm against B. subtilis in the leaf extracts of the plant grown in clay soil. The leaf extracts from the plant obtained from clay soil showed fungicidal activity against the Aspergillus species, while the other extracts only showed fungistatic effects against all sampled fungal species. The proximate content analysis revealed that carbohydrates and protein are the dominant nutrients in the leaf of C. spectabilis. Costus spectabilis is a plant that can be exploited for its medicinal, nutritional and economic values.