RESUMEN
It is estimated that 80% of all synthetic drugs are derived from medicinal plants, and nowadays, many synthetic drugs are derived from medicinal plants. Valeriana officinalis can treat many diseases of the nervous system. A crucial aspect of valerian extract is that it inhibits the proliferation of breast cancer cells. To optimize the yield of bioactive compounds in the V. officinalis root extraction, a response surface methodology-based D-optimal design was used. To fulfill this aim, the effects of various factors such as solvent type and concentration, mixing temperature, ultrasound time, and drying method were examined. The optimal conditions for solvent percentages, mixing temperature, ultrasound time, solvent type, and drying methods were determined to be 94.88%, 25 °C, 48.95 min, methanol, and microwave, respectively, with a desirability of 0.921. The predicted valerenic acid, total phenols, total flavonoids, and antioxidant activity in V. officinalis extract were 1.19 (mg/g DW), 8.22 (mg/g DW), 5.27 (mg/g DW), and 92.64%, respectively. In optimal conditions, the extracted amounts of valerenic acid, total phenols, total flavonoids, and antioxidant activity were 2.07 mg/g DW, 7.96 mg/g DW, 5.52 mg/g DW, and 78.68%, respectively, which were consistent with the model predicted amounts (based on 95% prediction interval). This study could be useful as a model for demonstrating the efficacy of microwave drying to maximize the biochemical content of V. officinalis, as well as the antioxidant activity of the root extracts of V. officinalis on industrial scale.
RESUMEN
For successful conservation and breeding of a medicinal species, it is important to evaluate its genetic diversity as well as its content of phytochemical compounds. The aim of the present study was to investigate the genetic variation of Iranian natural populations of W. somnifera and W. coagulans, using the RAPD (random amplified polymorphic DNA) markers, and their withaferin A content. Using 16 RAPD primers, a total of 282 RAPD bands were achieved. The highest and lowest percentages of polymorphism were observed with primers OPAD-15 (100.0%) and OPC-06 (75.0%), respectively. Cluster analysis of the genotypes was performed based on data from polymorphic RAPD bands, using Dice's similarity coefficient and the UPGMA clustering method. Variations in the RAPD results were found to reflect geographical distribution and genetic factors of the plant populations. The HPTLC analysis of the studied samples revealed the presence of withaferin A in W. coagulans and W. somnifera. Moreover, the concentration of withaferin A had a range from 2.2 to 32.5 microg/g DW and was higher in the aerial part than in the root in all used samples. The results of the present study show that there is a high level of variation in the Iranian natural population of Withania, which is significant for conservation and breeding programs to improve production of withaferin A.