In Vitro Production Of L-dopa In Tissue Cultures Of Banana

Nutraceutical Difference between Two Popular Thai Namwa Cultivars Used for Sun Dried Banana Products

Musa (ABB group) “Kluai Namwa” bananas (Musa sp.) are widely grown throughout Thailand. Mali Ong is the most popular Kluai Namwa variety used as raw material for sun-dried banana production, especially in the Bangkratum District, Phitsanulok, Thailand. The sun-dried banana product made from Nanwa Mali Ong is well recognized as the best dried banana product of the country, with optimal taste compared to one made from other Kluai Namwa varieties. However, the production of Mali Ong has fluctuated substantially in recent years, leading to shortages. Consequently, farmers have turned to using other Kluai Namwa varieties including Nuanchan. This study investigated the nutraceutical contents of two popular Namwa varieties, Mali Ong and Nuanchan, at different ripening stages. Nutraceuticals in the dried banana products made from these two Kluai Namwa varieties and four commercial dried banana products were compared. Results indicated that the content of moisture, total sugar, and total soluble solids (TSS) (°Brix) increased, while total solids and texture values decreased during the ripening stage for both Kluai Namwa varieties. Rutin was the major flavonoid found in both Namwa Mali Ong and Nuanchan varieties ranging 136.00−204.89 mg/kg and 129.15−260.38 mg/kg, respectively. Rutin, naringenin, quercetin and catechin were abundant in both Namwa varieties. All flavonoids increased with ripening except for rutin, gallocatechin and gallocatechin gallate. There were no significant differences (p < 0.05) in flavonoid contents between both varieties. Tannic acid, ellagic acid, gallic acid, chlorogenic acid and ferulic acid were the main phenolic acids found in Mali Ong and Nuanchan varieties, ranging from 274.61−339.56 mg/kg and 293.13−372.66 mg/kg, respectively. Phenolic contents of both varieties decreased, increased and then decreased again during the development stage. Dopamine contents increased from 79.26 to 111.77 mg/kg and 60.38 to 125.07 mg/kg for Mali Ong and Nuanchan, respectively, but the amounts were not significantly different (p < 0.5) between the two Namwa varieties at each ripening stage. Inulin as fructooligosaccharide (FOS) increased with ripening steps. Production stages of sun-dried banana products showed no statistically significant differences (p < 0.05) between the two Namwa varieties. Therefore, when one variety is scarce, the other could be used as a replacement in terms of total flavonoids, phenolic acid, dopamine and FOS. In both Namwa varieties, sugar contents decreased after the drying process. Sugar contents of the dried products were 48.47 and 47.21 g/100 g. The drying process caused a reduction in total flavonoid contents and phenolic acid at 63−66% and 64−70%, respectively. No significant differences (p < 0.05) were found for total flavonoid and phenolic contents between the dried banana products made from the two Namwa varieties (178.21 vs. 182.53 mg/kg and 96.06 vs. 102.19 mg/kg, respectively). Products made from Nuanchan varieties (24.52 mg/kg) contained significantly higher dopamine than that from Mali Ong (38.52 mg/kg). The data also suggest that the banana maturity stage for production of the sun dried products was also optimum in terms of high nutraceutical level.

Statistically optimized biotransformation protocol for continuous production of L-DOPA using Mucuna monosperma callus culture

L-DOPA (3,4-dihydroxyphenyl-L-alanine), a modified amino acid, is an expansively used drug for the Parkinson’s disease treatment. In the present study, optimization of nutritional parameters influencing L-DOPA production was attempted using the response surface methodology (RSM) from Mucuna monosperma callus. Optimization of the four factors was carried out using the Box–Behnken design. The optimized levels of factors predicted by the model include tyrosine 0.894 g l^-1, pH 4.99, ascorbic acid 31.62 mg l^-1and copper sulphate 23.92 mg l^-1, which resulted in highest L-DOPA yield of 0.309 g l^-1. The optimization of medium using RSM resulted in a 3.45-fold increase in the yield of L-DOPA. The ANOVA analysis showed a significant R² value (0.9912), model F-value (112.465) and probability (0.0001), with insignificant lack of fit. Optimized medium was used in the laboratory scale column reactor for continuous production of L-DOPA. Uninterrupted flow column exhibited maximum L-DOPA production rate of 200 mg L^-1 h^-1 which is one of the highest values ever reported using plant as a biotransformation source. L-DOPA production was confirmed by HPTLC and HPLC analysis. This study demonstrates the synthesis of L- DOPA using Mucuna monosperma callus using a laboratory scale column reactor.

Optimization of L-DOPA production by Brevundimonas sp. SGJ using response surface methodology

l‐DOPA (3,4‐dihydroxyphenyl‐l‐alanine) is an extensively used drug for the treatment of Parkinson's disease. In the present study, optimization of nutritional parameters influencing l‐DOPA production was attempted using the response surface methodology (RSM) from Brevundimonas sp. SGJ. A Plackett–Burman design was used for screening of critical components, while further optimization was carried out using the Box–Behnken design. The optimized levels of factors predicted by the model were pH 5.02, 1.549 g l⁻¹ tryptone, 4.207 g l⁻¹l‐tyrosine and 0.0369 g l⁻¹ CuSO₄, which resulted in highest l‐DOPA yield of 3.359 g l⁻¹. The optimization of medium using RSM resulted in a 8.355‐fold increase in the yield of l‐DOPA. The anova showed a significant R² value (0.9667), model F‐value (29.068) and probability (0.001), with insignificant lack of fit. The highest tyrosinase activity observed was 2471 U mg⁻¹ at the 18th hour of the incubation period with dry cell weight of 0.711 g l⁻¹. l‐DOPA production was confirmed by HPTLC, HPLC and GC‐MS analysis. Thus, Brevundimonas sp. SGJ has the potential to be a new source for the production of l‐DOPA.