Antioxidant and antidiabetic properties of Garcinia cowa Roxb. extracts from leaves, fruit rind, and stem bark in different solvents

The objective of this investigation was to assess the antioxidant and antidiabetic abilities of Garcinia cowa Roxb., a Thai native plant that has a history of use in traditional medicine in several countries. To achieve this goal, different plant parts, such as the leaves, fruit rind, and stem bark, were subjected to extraction with hexane, ethyl acetate, and 70% ethanol using the maceration method. The Folin-Ciocalteu technique was used to quantify the extracts' total phenolic content (TPC). The antioxidant assays, including DPPH, ABTS, and FRAP, and antidiabetic properties through the alpha-amylase and alpha-glucosidase inhibitory capacities of different extracts from G. cowa were assessed. The results revealed that the stem bark extracted with ethyl acetate displayed the highest level of TPC at 153.68 mg GAE/100 g DW. Compared to the other extracts, the stem bark ethyl acetate extract demonstrated the highest antioxidant activity in DPPH, ABTS, and FRAP assays with values of 436.86, 359.17, and 526.98 µmol TE/100 g DW, respectively. Further examination of the antidiabetic effects of stem bark extract in ethyl acetate exhibited the highest alpha-amylase and alpha-glucosidase inhibitory activities with IC50 values of 12.54, and 8.48 mg/mL, respectively. The findings of this research provide initial indications that G. cowa has both antioxidant and antidiabetic attributes and could be viewed as a potential therapeutic agent for managing diabetes

Antioxidant and lipid peroxidation inhibitory potentials of the unripe and ripe of Citrus mitis Blanco pulps and peels from south Thailand

Citrus mitis Blanco fruit contains high levels of vitamin C, phenolics, and flavonoids, which exhibit a wide range of beneficial biological effects. The current research aimed to evaluate the levels of vitamin C, flavonoid, total phenolic contents, and antioxidant properties, as well as the inhibitory effects on lipid peroxidation, in both unripe and ripe fruit tissues (pulps and peels) of C. mitis Blanco. The fruit tissues were obtained from the Hat Som Paen subdistrict in Ranong province, located in the southern region of Thailand. Fruit tissues were extracted using maceration with 80% ethanol and water solvents. Vitamin C quantification was achieved using the 2,6-dichloroindophenol titrimetric method. Total flavonoid content was determined using the aluminium chloride colorimetric method, while total phenolic content was assessed using the Folin-Ciocalteu procedure. Additionally, ABTS and DPPH assays were used to assess the antioxidant properties. The measurement of lipid peroxidation inhibitory activity was carried out using the thiobarbituric acid reactive substances (TBARS) assay. The findings indicated that the water extract exhibited higher levels of vitamin C compared to the 80% ethanolic extract. In contrast, the 80% ethanolic extract revealed greater amounts of total phenolic and flavonoid contents than the water extract. The water extract of unripe pulp exhibited the highest vitamin C content among all the extracts, reaching 36.74 mg/100 g fresh weight (FW). The 80% ethanolic extract of unripe peel demonstrated the highest level of total phenolic content (35.67 mg gallic acid equivalent (GAE)/g extract), while ripe peel exhibited the highest total flavonoid content (16.88 mg catechin equivalent (CE)/g extract). Both unripe and ripe fruit extracts exhibited antioxidant and lipid peroxidation inhibitory activities. The 80% ethanolic extract from unripe peel demonstrated the most significant antioxidant activities against DPPH (6.31 mg trolox equivalent (TE)/g extract) and ABTS (7.69 mg TE/g extract). Moreover, the 80% ethanolic extract of unripe peel showed the highest level of inhibitory activity against lipid peroxidation, with a value of 74.62%. These results underscore the potential bioactivities of unripe and ripe C. mitis Blanco fruit tissues, which can offer nutritional and health benefits. These properties make them particularly valuable in the food industry due to their excellent antioxidant and lipid peroxidation inhibitory characteristics

การเพาะเลี้ยงเยื่อเพื่อการขยายพันธุ์และการชักนำเหง้าขนาดเล็กจากว่านชักมดลูกตัวเมีย Curcuma comosa roxb

วารสารวิชาการและวิจัย มทร.พระนคร, ปีที่ 16, ฉบับที่ 2 (ก.ค.-ธ.ค. 2565), หน้า 13-23This study was conducted to determine the effects of plant growth regulators on in vitro propagated plantlets and microrhizome inductions of Curcuma comosa Roxb. for an efficient development of plant regeneration. In vitro sprouted shoots (2 cm length) of C. comosa were incised in longitudinal section and subcultured on MS media supplemented with 3 mg/L BA for shoot multiplication and plant regeneration. Subsequently, the regenerated plants were transferred to MS medium with various concentrations of plant growth regulators; BA (1, 3, 5 mg/L), kinetin (1, 3, 5 mg/L) and TDZ (0.5, 1, 1.5 mg/L). The result showed that MS medium supplemented with 3 mg/L BA was the most effective in shoot induction with the significantly maximum average number of 2.11 shoot buds per responding explant. Moreover, MS medium supplemented with 1 mg/L BA produced the longest average of shoot bud explants (12.99 cm), while the basal MS medium induced the longest average of root multiplication (6.63 cm). Furthermore, microrhizome induction was produced under in vitro conditions derived young shoot buds upon transfer to MS medium containing various combinations of 1, 3 and 5 mg/L BA and 30, 60 and 90 g/L sucrose concentrations. The optimum combination in the induction of significantly highest average length of both stem (18.32 cm) and root (7.52 cm) multiplication was obtained on MS basal medium supplemented with 1 mg/L BA and 30 g/L sucrose for 4 weeks. Although microrhizome formation was not produced by the different amount of BA and sucrose in induction medium, starch accumulation was found at the base of the stem explants cultured on MS medium containing 60 and 90 g/L sucrose concentrations. Additionally, in vitro propagated C. comosa plantlets through microrhizome induction were grown under greenhouse conditions for 4 weeks and further developed into normal plants, resulting in successfully high survival rates of 66 – 100% in the cultivated C. comosa.Rajamangala University of Technology Phra Nakho