The study was conducted to analyze some of the bioactive compounds and the antioxidant capacity of Tinospora crispa stem extract. Tinospora crispa stem extract is a prerequisite for the production of products capable of supporting and treating diseases. Tinospora crispa stem extract is made by immersion method withsolvents (water, ethanol 80o and methanol)  and combined with ultrasound. Antioxidant activities were tested using DPPHmethods and phenolic, flavonoid, polysaccharide, tannin content were determined by the spectrophotometer method. The results showed that the moisture content was 61.09% and high extraction efficiency of Tinospora crispa stem were between 3.69% and 6.95% respectively. The extract of Tinospora crispa stem contains the presence of biological compounds such as alkaloids, flavonoids, saponin, steroids, tannins and phenols. The phenolic, flavonoid, polysaccharide and tannin content of Tinospora crispa stem were318.91 mg gallic acid/g dry; 36.71 mg quercetin/g dry; 10.38 mg GE/g dry and 38.42 mg tannic acid/g dry respectively. Tinospora crispa stem has antioxidant ability by DPPH method with IC50 value of water, ethanol 80o and methanol 113.69 mg/mg; 89.12 mg/mg; 62.19 mg/mg, respectively. Thus, the Tinospora crispastem extract had bioactive compounds and antioxidant activities, is a potential source of raw materials for research and applications.

The research was conducted to evaluate the antioxidant activity of carotenoid extract from bacteria strainsisolated in An Giang Province. There by, the strain of bacteria with the best antioxidant capacity was selected. The results of DPPH free radical reduction survey on crude carotenoid extracts of the tested bacterial strains showed that all the crude carotenoid extracts of these strains have good DPPH free radical reductionability. Carotenoid extracts from strains NC4-3, NC8-3, NC1-6, NC3-3 and NC7-4 have IC50 values of 2,88; 3,30; 3,45; 5,15 và 9,05 mg/mL, respectively. This showed that the carotenoid extracts of these clones have lower antioxidant activity than the b-carotene control (IC50 = 2,70 mg/mL). Remarkably, the carotenoid extract of theNC4-3 strain had the best antioxidant activity of the 5 strains examined (IC50 = 2,88 mg/mL), only lower than the antioxidant activity of the control sample bcarotene.

The study was conducted to analyze some of the bioactive compounds and the antioxidant capacity ofLantana camara leaves extract. This research was a prerequisite for the production of products with capability of supporting and treating diseases. L. camara leaves extract was extracted by combining the immersion method with different solvents (water, ethanol 80o and methanol) and ultrasound. Oxidation resistance wastested by DPPH method and the con tent of phenolic, flavonoid, polysaccharide, tannin were determined by the spectrophotometer method. The results showedthat the moisture content was 67.8% and extraction efficiency of L.camara leaves ranged from 4.29% to 6.13%. The extract of L. camara leaves contained biological compounds such as alkaloids, saponin, flavonoids, steroids, tannins and phenols. The phenolic, flavonoid, polysaccharide and tannin content of L. camara leaves per g of dry weight were 251.52 mg gallicacid/g; 41.58 mg quercetin/g; 11.06 mg GE/g and 34.44 mg tannic acid/g, respectively. L.camara leaves has antioxidant ability by DPPH method with IC50 value of water, ethanol 800 and methanol 259.11 mg/mg; 150.29 mg/mg; 75.43 mg/mg, respectively. The results indicated that L. camara leaves contains many anti-oxidativebioactive ingredients, which were potential materials for further research and applications.

Prodigiosin is a red pigment and widely applied as antimicrobial, antifungal, anti-malarial, anti-cancer, ,...Prodigiosin is isolated from bacteria, such as Serratia marcescens, Hahella chejuensis, Vibrio psychroerythrus and Streptomyces coelicolor,. . . S. marcescens is the major producer of prodigiosin. The production of prodigiosin has been shown to be influenced by many factors, such as species type and environmental factors, including media composition, temperature, pH and incubation time,... This study was conducted to analyze the effect of various factors on prodigiosin production process of S. marcescens SR3 by submerged fermentation method. Prodigiosin content was determined by the spectrophotometer method. The results showed thatS. marcescens SR3 could produce prodigiosin in LB medium, initial bacterial volume (7%, v/v), carbon source (lactose 1 g/L), nitrogen source (yeast extract 5 g/L), pH = 8, fermentation time (96 hours), and prodigiosin content reached 527.28 Unit/cell. The results of the study showed that S. marcescens SR3 bacteria is a potential source of prodigiosin for research and applications.