Detection and mode of action of retinoids on ovarian development in the mud crab, Scylla serrata

In the current study, the retinoic acid isomers such as 9-cis retinoic acid and all-trans retinoic acid were detected in the mature ovaries of mud crabs, Scylla serrata using HPLC analysis. Given the detection of retinoids in the ovaries, an attempt has been made to elucidate the possible role of retinoic acid in the regulation of reproduction in mud crabs. Injection of 9-cis retinoic acid induced ovarian maturation in intact mud crabs as evidenced by a significance elevation in the ovarian index (226.76%; P<0.001), and oocyte diameter (150.61%; P<0.001) accompanied by accumulation of yolk globules in the oocytes as compared to the untreated crabs. Further, a significant increase (258.63%; P<0.0001) in the circulatory ecdysteroid levels were also observed in 9-cis retinoic acid injected mud crabs over vehicle injected crabs. From the results, it can be postulated that retinoic acid-induced stimulation of ovarian maturation at least in part mediates ecdysteroids in the mud crabs., 0.371 and 0.217 year-1, respectively and the exploitation rate was calculated as 0.369

Effect of selected retinoids on carbohydrate metabolism in the freshwater monsoon prawn, Macrobrachium malcolmsonii

Retinoic acid isomers such as 9 cis retinoic acid (9CRA) and all trans retinoic acid (ATRA) have been discovered in crustaceans. However, their physiological significance in the biological framework of crustaceans is unclear. The present study evaluates the effect of retinoic acid on the hemolymph glucose levels in the monsoon prawn, Macrobrachium malcolmsonii. Injection of 9CRA into intact prawns significantly elevated the hemolymph glucose levels in a dose-dependent and time-dependent manner. However, such hyperglycemic response in 9CRA-injected eyestalk ablated (ESX) prawns was not observed. No changes in the hemolymph glucose levels were noticed in ATRA-injected intact or ESX prawns. Bilateral ESX showed significant elevation in the total carbohydrates and glycogen levels with a significant reduction in the activity levels of phosphorylase activity in the crustacean hyperglycaemic hormone (CHH) target tissues, hepatopancreas and muscle of prawns. Injection of 9CRA into intact prawns showed significant elevation in the activity levels of phosphorylase activity with a concomitant decrease in the total carbohydrates and glycogen levels in the CHH target tissues compared to vehicle-injected prawns. No significant differences were observed in the selected biochemical variables in 9CRA-injected prawns over 9CRA-injected ESX prawns. The expression levels of CHH in the eyestalks of 9CRA-injected prawns were significantly elevated over its respective control. It can be concluded that 9CRA-induced hyperglycemia, at least in part, mediates CHH in M. malcolmsonii

Purification, Structural Elucidation, and Anticancerous Properties of a Novel Flavonoid from Flowers of Leucas indica

Previously, we showed that the crude methanol extracts of Leucas indica flowers exhibited antioxidant properties and in the current study, crude methanol flower extracts of L. indica showed anticancerous properties as evidenced cytotoxicity (MTT assay test) against the selected cancerous cell lines HeLa, HCT116, HL-60, and MCF-7. Therefore, further analysis was performed to isolate and purify the bioactive compound using activity-guided repeated fractionation of the methanol extract by silica gel column chromatography. After collection of different fractions, all the fractions were subjected to TLC analysis and the fractions which yielded the same compounds on TLC were further analyzed for physicochemical and spectroscopic analyses, e.g., UV, IR, 1H NMR, 13C NMR, COSY, HSQC, and mass spectroscopy. The bioactive compound isolated was elucidated as 6-hydroxy-3-(4-hydroxyphenyl)-7-(3,4,5-trihydroxy-6-)(hydroxymethyl)tetrahydro-2H-pyran-2yl)-4H-chromen-4-one. Based on the antioxidant and anticancerous properties, L. indica might be a promising source of useful natural products and the newly bioactive compound might offer opportunities to develop new anticancerous drugs