In this study, chitosan nanoparticles were used as a carrier for Protocatechuic acid (PCA) to resist Pyricularia oryzae against rice blast. The final compound was characterized using zeta potentials for its surface electricity, Fourier transform infrared (FT-IR) analysis and transmission electron microscopy (TEM) were conducted for functional groups and for particle sizes and shape, respectively. The zeta potential results showed that loading PCA causes chitosan nanoparticle (CSNP) to decrease in surface electrons. The TEM images revealed that the particle size of chitosan (CS), although increasing in size when carrying PCA molecules, showed sufficient size for reasonable penetration into fungal cells. The FT-IR analysis showed that all functional group in CSNP carried PCA matched with previous studies. The antifungal test showed that diameters of inhibition zone of CS increases significantly after loading PCA, exhibiting the strongest antimicrobial effect on the Pyricularia oryzae fungus compared with weaker effects exhibited by CSNP alone or PCA. Our results suggested that CSNP loaded with PCA could be a potential compound for eradication of Pyricularia oryzae and that further testing on in vitro rice plants is recommended to reaffirm this possibility.

In Vietnam, the aerial parts of Ruellia tuberosa L. are used to treat stress oxidation and inflammatory symptoms in diabetes mellitus. The present study was designed to determine the antioxidant and inflammatory inhibition activities of Ruellia tuberosa L. extract (RTE) and those of the isolated compounds by column chromatography. The crude ethanol extract and ethyl acetate fraction exhibited potent antioxidant activity in the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) assays with an IC₅₀ of 25.18 and 14.71 (DPPH test) and 18.22 and 15.27µg/ml (ABTS test), respectively. The RTE contained high concentrations of polyphenols (308.21mg GAE/g) and moderate concentrations of flavonoids (97.80mg QE/g). In the anti-inflammatory screening assay, the crude ethanol extract, ethyl acetate, and methanol fractions suppressed the release of IL-6 and nitric oxide production, but the production of IL-10 was not enhanced in LPS-induced RAW 264.7cells. Three potential anti-inflammatory compounds as hispidulin (6), physalin E (7), and physalin D (8) along with five other compounds named myricitrin (1), afzelin (2), apigenin (3), taraxerol (4), and lupeol (5) were isolated and identified from the ethyl acetate fraction. Physalin D (8) exhibited a strong, dose-dependent anti-inflammatory activity by inhibiting the production of IL-6 proinflammatory cytokines; however, the IL-10 expression was independent of its concentration in macrophages at noncytotoxic concentrations ranging from 5 to 40μg/mL. Based on the data obtained, compounds 68 sourced from Ruellia tuberosa L are potentially bioactive compounds for the treatment of inflammation symptoms in type 2 diabetes mellitus.

Cassia grandis is used for the treatment of skin disorders, back pain, aches, etc. in Vietnamese traditional medicine. In this paper, phytochemicals of the leaves were investigated. A new naphthalene derivative (1, cassgranon D) and, seven known compounds rutin (2), afzelin (3), quercitrin (4), epicatechin (5), (-)-epiafzelechin (6), isoquercitrin (7) and aloe emodin (8) were isolated from the ethyl acetate and methanol extracts. Their structures were elucidated by spectral evidences (UV, IR, MS, ¹H, ¹³C, DEPT, HSQC and HMBC NMR), as well as by comparing with published data.

Launaea sarmentosa (Willd) Schultz-Bip.ex Kuntze, a creeping herb, belongs to family Asteraceae. It is distributed in sandy coasts of India, Sri Lanka, Malaysia, East Africa and Vietnam. In Vietnamese folk medicine, whole plant possess tonic, soporific, diuretic, laxative properties and the roots are used to benefit milk for mothers after childbirth, instead of Lactuca indica. Up to now, the phytochemicals and bioactivities of this plant are not yet been examined. The present study was designed to investigate the saponin, polyphenol and flavonoid contents as well as α-glucosidase inhibitory and antioxidant activities of the leaves of L. sarmentosa. Preliminary phytochemical screening of this plant were found to give positive reactions for flavonoid, saponin, alkaloid, tannin, and steroid compounds. The result of quantitative determination showed that the leaves contains high amount of polyphenol compounds (290.90 mg GAEs/g extract), lower amount of flavonoids (85.47 mg QEs/g extract) and the saponin content was found to be 10.8 % (per dry weight). As expected, the ethanol extract had a antioxidant potential with IC₅₀ value of 24.15 μg/mL in DPPH experiment, compared to that of vitamin C. Meanwhile, the α-glucosidase inhibitory assay showed inhibited enzyme activity with IC₅₀ value of 67.09 μg/ml.

Citrus hystrix which is commonly known as Kaffir Lime, is a plant with great potential for research and commercialization. C. hystrix essential oil is used as a fragrance to increase appetite in food, or sweet-smelling in cosmetics and antibacterial properties in the health field. Most research have focused on the peels, yet the EO content in C. hystrix leaves is also noteworthy. There are many essential oils extraction methods from conventional to advanced techniques. However, it is necessary to consider the influence of heat during heat transfer to constituents in materials, which easily decompose the volatile compounds contained in the essential oil. Steam distillation method can limit this disadvantage by separating the solvents and materials into two places that are only connected by a steam pipe. In this study, the steam distillation method was employed to extract the EOs from C. hystrix leaves. The chemical components in this EOs was evaluated by gas chromatography–mass spectrometry (GC-MS) method. C. hystrix leaves achieved an essential oil yield of 1.24%. Moreover, different compounds in Kaffir Lime EOs obtained from steam distillation method were identified, including β-citronellol, citronellyl acetate, linalool, caryophyllene, pinene, sabinene, and naphthalene. Findings from the present study provide helpful insights to effective essential oil extraction from C. hystrix leaves with high content of valuable phytochemical compounds.