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Plant cell cultures are a valuable resource for the exploration, isolation, and production of metabolites of pharmaceutical interest. Antimicrobial activity against Escherichia coli, Salmonella typhimurium, Bacillus cereus, and Streptococcus aureus, of ethanolic extracts of cell suspension culture of Thevetia peruviana, has been previously demonstrated and associated with the flavonoids content such as dihydroquercetin (DHQ). This study evaluated the influence of three extraction methods on antioxidant activity (AA) and DHQ content in ethanolic extracts of T. peruviana cells grown in a bioreactor and harvested in the stationary phase. The extractions were developed by shaking, bath ultrasound, and probe ultrasound (PUS) with 20, 50, and 80% v/v ethanol. DHQ concentration was determined by high-performance liquid chromatography and AA by 2,2-diphenyl-1-picrylhydrazyl colorimetric assay. PUS (frequency 50 MHz, power 20% and 80% ethanol) significantly improved (p-value < 0.05) the extraction of flavonoids = 127.51±4.09 mg quercetin-equivalents/gram dry weight (g.d.w); DHQ = 512.07 μg/g.d.w and AA = 44.50±3.67 mg Trolox-equivalents/g.d.w. The development of a method that maximizes the biotechnological production of DHQ, is highlighted. This compound is a potential agent against S. aureus methicillin-resistant. [ABSTRACT FROM AUTHOR]

Thevetia peruviana is a tropical plant with antioxidant and antimicrobial properties attributed to flavanone and flavonol glycosides that are characteristic of this species. The influence of the exogenous addition of the phytohormones methyl jasmonate-MJ and salicylic acid-SA on the production of phenolic compounds (PC) in suspension cell cultures of T. peruviana was evaluated. Shake-flask scale cultures were elicited with MJ (3 μM), SA (300 μM), and MJ/SA (3 μM/300 μM); cells were harvested every 24 hours postelicitation for 6 days. Profile of PC was determined in ethanolic extracts by high performance liquid chromatography coupled to diode array detector (HPLC-DAD) and proton nuclear magnetic resonance spectroscopy (1H-NMR). MJ significantly increased the hydroxycinnamates production such as ferulic acid (FA) and polyphenols such as chlorogenic acid (CGA), and decreased flavonols production such as dihydroquercetin (DHQ). Salicylic acid increased the benzoic acid derivatives (BA) production. In contrast, simultaneous treatment with MJ/AS inhibited the CQA and FA production, while increased the DHQ biosynthesis. In conclusion, simultaneous treatment with MJ and SA results in an antagonistic effect on the production of flavonoids from T. peruviana. It is possible that salicylates suppress some aspects of the jasmonate signaling [ABSTRACT FROM AUTHOR]