The changes in morphogenesis and bioactivity of Tetradenia riparia, Mondia whitei and Cyanoptis speciosa by an aeroponic system

Abstract

An aeroponic system provides an opportunity for improving quantity, quality, consistency and biomass production of roots of medicinal plants. Evaluation of bioactivity is required for establishing biomass from an aeroponic system for commercial production and traditional medicinal use. The present study evaluated antibacterial, antiplasmodial and cytotoxicity properties of three-month-old Tetradenia riparia, Cyanoptis speciosa and Mondia whitei maintained in an efficient aeroponic system in a greenhouse. The species were selected based on the importance of their roots in traditional medicine and their current conservation status. The plant biomass (leaf, stem and root) varied between the same age of greenhouse (rooted stem cuttings of T. riparia and C. speciosa and somatic embryo-derived M. whitei grown ex vitro) and aeroponic-grown plants. The root biomass was significantly higher in aeroponic-grown M. whitei and T. riparia. The aeroponic-grown M. whitei and T. riparia roots showed best antibacterial activity (MIC of 0.195–0.78mg/ml−1) against both Gram-positive (Enterococcus faecalis, Staphylococcus aureus, Micrococcus luteus and Bacillus subtilis) and Gram-negative (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) bacteria. Besides the root extract of greenhouse-grown M. whitei (IC50=12.1μg/ml−1) that exhibited better antiplasmodial activity than its aeroponic counterpart (IC50=22.0μg/ml−1), the highest antiplasmodial activities were observed in the aeroponic-grown plants. All the extracts (both aeroponic and greenhouse-grown plants) which displayed good antiplasmodial activity also had a good selectivity index. The present study revealed that the aeroponic system could be used to produce clean, high-quantities and excellent quality of roots of T. riparia, M. whitei and C. speciosa for basic pharmacological research. In addition, aeroponic-grown T. riparia and M. whitei plants facilitate commercial and rapid propagation for therapeutic potential and conservation purposes. It also could satisfy traditional medicine and pharmaceutical industry demands.