Search

Summary: Fenugreek microgreen and mint leaf displayed antidiabetic potential during in vitro assays including cell line‐based analysis. Aqueous fenugreek microgreen extract (FME) (2 mg mL−1) inhibited α‐amylase by 70%. It also enhanced glucose uptake in L6 cells by 25% at 10 mg mL−1 which further improved to 44% in the presence of insulin. On the other hand, fresh mint leaf extract (MLE) inhibited α‐glucosidase up to 90% and increased glucose uptake by 15% in HepG2 cells. Besides, both these extracts also inhibited nonenzymatic glycation of protein. FME and MLE were also found to have high levels of total phenolics, flavonoids and antioxidants which could play a possible role in the observed antidiabetic activity. As blood glucose levels in diabetes can be regulated by inhibition of enzymes regulating carbohydrate metabolism and improving glucose uptake in cells, the findings indicate a complimentary therapeutic role of these two dietary herbs in diabetes. [ABSTRACT FROM AUTHOR]

Xanthomonas campestris strains have been reported to undergo programmed cell death (PCD) in a protein rich medium. Protein hydrolysates used in media such as nutrient broth comprise of casein digest with abundance of proline and glutamate. In the current study, X. campestris pv. campestris (Xcc) cells displayed PCD when grown in PCD inducing medium (PIM) containing casein tryptic digest. This PCD was also observed in PCD non-inducing carbohydrate rich medium (PNIM) fortified with either proline or proline along with glutamate. Surprisingly, no PCD was noticed in PNIM fortified with glutamate alone. Differential role of proline or glutamate in inducing PCD in Xcc cells growing in PNIM was studied. It was found that an intermediate product of this oxidation was involved in initiation of PCD. Proline oxidase also called as proline utilization A (PutA), catalyzes the two step oxidation of proline to glutamate. Interestingly, higher PutA activity was noticed in cells growing in PIM, and PCD was found to be inhibited by tetrahydro-2-furoic acid, a competitive inhibitor of this enzyme. Further, PCD was abolished in Xcc ΔputA strain generated using a pKNOCK suicide plasmid, and restored in Xcc ΔputA strain carrying functional PutA in a plasmid vector. Xanthomonas cells growing in PIM also displayed increased generation of ROS, as well as cell filamentation (a probable indication of SOS response). These filamented cells also displayed enhanced caspase-3-like activity during in situ labeling using a fluorescent tagged caspase-3 inhibitor (FITC-DEVD-FMK). The extent of PCD associated markers such as DNA damage, phosphatidylserine externalization and membrane depolarization were found to be significantly enhanced in wild type cells, but drastically reduced in Xcc ΔputA cells. These findings thus establish the role of PutA mediated proline oxidation in regulating death in stressed Xanthomonas cells. [ABSTRACT FROM AUTHOR]

Xanthomonas campestris strains have been reported to undergo programmed cell death (PCD) in a protein rich medium. Protein hydrolysates used in media such as nutrient broth comprise of casein digest with abundance of proline and glutamate. In the current study, X. campestris pv. campestris (Xcc) cells displayed PCD when grown in PCD inducing medium (PIM) containing casein tryptic digest. This PCD was also observed in PCD non-inducing carbohydrate rich medium (PNIM) fortified with either proline or proline along with glutamate. Surprisingly, no PCD was noticed in PNIM fortified with glutamate alone. Differential role of proline or glutamate in inducing PCD in Xcc cells growing in PNIM was studied. It was found that an intermediate product of this oxidation was involved in initiation of PCD. Proline oxidase also called as proline utilization A (PutA), catalyzes the two step oxidation of proline to glutamate. Interestingly, higher PutA activity was noticed in cells growing in PIM, and PCD was found to be inhibited by tetrahydro-2-furoic acid, a competitive inhibitor of this enzyme. Further, PCD was abolished in Xcc ΔputA strain generated using a pKNOCK suicide plasmid, and restored in Xcc ΔputA strain carrying functional PutA in a plasmid vector. Xanthomonas cells growing in PIM also displayed increased generation of ROS, as well as cell filamentation (a probable indication of SOS response). These filamented cells also displayed enhanced caspase-3-like activity during in situ labeling using a fluorescent tagged caspase-3 inhibitor (FITC-DEVD-FMK). The extent of PCD associated markers such as DNA damage, phosphatidylserine externalization and membrane depolarization were found to be significantly enhanced in wild type cells, but drastically reduced in Xcc ΔputA cells. These findings thus establish the role of PutA mediated proline oxidation in regulating death in stressed Xanthomonas cells. [ABSTRACT FROM AUTHOR]

ABSTRACT A dose of 0.5 kGy of gamma radiation in combination with low temperature storage (4C) helped in extending the shelf life of two Indian litchi ( Litchi chinensis) cultivars ('Shahi' and 'China') up to 28 days. However, during storage, pericarp browning in litchi was observed. Hence, in the current study to understand the mechanism of pericarp browning, total phenolics and the activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL) were evaluated. The PPO activity and phenolics were found to be higher in 'China' than in 'Shahi,' whereas POD and PAL activities were higher in 'Shahi.' PPO and phenolics played a major role in the pericarp browning. Radiation treatment increased the PAL activity and hence the level of total phenolics, whereas PPO and POD activities were inhibited. This may explain reduction in browning in irradiated fruits compared with nonirradiated fruits. PRACTICAL APPLICATIONS Browning of litchi pericarp affects the appeal of the fruit and is one of the main problems encountered by the cultivators and traders, leading to significant economic losses. Understanding the role of different enzymes and level of phenolics in the process of browning will help find suitable postharvest methods for the control of browning. As the radiation treatment is being used as a mandatory quarantine treatment in many countries for export, further understanding the effect of radiation treatment on the browning and related enzyme activities will help in postharvest management and improving international trade of litchi. [ABSTRACT FROM AUTHOR]