Effects of light, sucrose concentration and repetitive subculture on callus growth and medically important production in Justicia gendarussa Burm.f.

OBJECTIVE: This research aimed at the discovering the effects of light, sucrose concentration and repetitive subculture on the growth of Justicia gendarussa Burm.f. calluses based on biomass, morphological characters and metabolic profiles. METHODS: The second and third leaves of young J. gendarussa Burm.f. were isolated and cultured in solid Murashige and Skoog (MS) medium with the addition of 1 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg/L benzyl amino purine (BAP). Different sucrose concentrations, varying from 0 to 5%, were included in the medium. The cultures were incubated under light and dark conditions for 6 weeks. Repetitive subculture was carried out every 2 weeks for a total of four times, and 3% sucrose gave the best callus growth. Dry calluses were extracted with methanol, and their metabolic profiles were analyzed using gas chromatography/mass spectrometry (GC/MS). Compound identification was performed by comparing the mass spectra to references from the WILEY version 7n.1 library. RESULTS: Among the 12 conditions tested for the prolonged 6-week culture, the 2–5 % sucrose treatments under light and 3–5 % sucrose treatments under dark exhibited the highest dry weight. For repetitive subculture, the highest wet and dry weights were identically detected under both light and dark conditions after the second repetitive subculture. A total of 19 metabolites was identified by GC/MS, with major compounds being taraxasterol, monoplex D, 2-methoxy-4-vinylphenol, and palmitic acid. CONCLUSION: Light, sucrose concentration, and repetitive subculture all significantly impacted the growth and metabolic profiles of J. gendarussa Burm.f. calluses. A concentration of 3% sucrose demonstrated the best growth of callus and could be further applied for mass production.