Mangiferin (C₁₉H₁₈O₁₁) is a C-glucoside xanthone that is mainly found in the leaves of mango (Mangifera indica L). The compound has been recognized for several pharmacological values, including antioxidant and antibacterial activities. Therefore, the present study aims to utilize the old leaves of mango as a potential source for mangiferin extraction and purification, and evaluate its antimicrobial and antioxidant properties. In the present study, mangiferin was extracted from a local variety of mango leaves using ultrasonic-assisted extraction methods and ethanol as the extraction solvent. The crude ethanolic extract of mangiferin was then purified by the liquid–liquid fractionation method with dichloromethane and ethyl acetate, then further separated by HPLC. The crude extract, ethyl acetate fractions and purified mangiferin were investigated for anti-microorganism activity against Escherichia coli, Salmonella spp. and Aspergillus flavus by using the paper disc diffusion assay. The results have shown that the extraction efficiency was 14.17%. The obtained mangiferin was 1.97 g of content and 94.2% of purity. The oxidation resistance of purified mangiferin was 1.77 times higher than the crude extract and 1.05 times higher than the standard mangiferin (IC₅₀ = 13.841 μg/mL). However, the purified mangiferin has shown no inhibitory action against the experimental strains of microorganisms. The findings from the present study suggest an effective scheme of extraction and purification to obtain mangiferin from the local variety of mango with high purity and antioxidant potential.

Background: DNA barcoding is a relatively new method of identifying plant species using short sequences of chloroplast DNA. Although there is a large number of studies using barcoding on various plant species, there are no such studies in the genus Nelumbo. Methods: Three chloroplast DNA regions (rbcL, matK, trnH-psbA) were tested for their suitability as DNA barcoding regions of thirty three lotus samples which were collected in Thua Thien Hue province, Vietnam. Universal primers were used and sequenced products were analyzed using Minimum Evolution method in the MEGA 7.0 program.Result: We did not observe high variability in nucleotide sequences within the rbcL region (0.135%). White Nelumbo, while, the most encoding matK (8.013%) and variable trnH-psbA (with different number of repeating regions TAAAA) intergenic regions was the most useful for Nelumbo barcoding. Individual application of the studied regions did not provide the expected results. None of the regions used in the study allowed the division of white and pink lotus varieties of N. nucifera specie according to the adopted classification of the genus Nelumbo. The results confirm that the use of matK, rbcL and trnH-psbA or combine all three regions together is insufficient for DNA barcoding in white and pink lotus varieties of N. nucifera specie and better discrimination within the genus Nelumbo. Our results also indicate the necessity of using a different region. All of the new sequences have been deposited in GeneBank under the following accession numbers: rbcL (MN011708 to MN068956); matK (MN011719 to MN068978) and trnH-psbA (MN011730 to MN086252).

This study was carried out to optimize the various approaches to analyze the effects of various variables on the total flavonoid content extraction from the roots of Helicteres hirsuta L. The existence of various compounds in the methanol fraction was accessed by using LC-MS/MS analysis. The results of the study identified the ideal parameters such as times (30 minutes); methanol solvent concentration (50%); ultrasonic frequency (12 Hz); and material/solvent ratio [1:30 (w/v)] for extracting the highest total flavonoids from the roots of H. Hirsuta. The study's results suggested that the total flavonoid value was 3.52684 (mg Catechin/g extract). The verified experiment obtained an actual value of 5.205 (mg Catechin/g extract). Further, the results of the study suggested the presence of 20 compounds of a flavonoid nature (66.667%) appearing in the purified methanol fractional extract. These compounds can inhibit DPPH free radicals at 50%, with an IC50 value of 536.760 g/mL, and they also have inhibitory activity on the growth of cancer cell lines with IC50 values ranging from 115.81 and 219.17g/mL. The human leukemia cell line (HL-60) exhibits the most significant cytotoxic response to a methanol extract from H. hirsuta root with an IC50 value of 115.81 g/mL.

Background: The internal transcribed spacer (ITS) of nuclear ribosomal DNA is one of the most commonly used DNA markers in plant phylogenetic and DNA barcoding analyses, and it has been recommended as a core plant DNA barcode. To compare and find out the analysis genetic diversity difference some pepper individuals collected in different localities in Vietnam when using the ITS of nuclear ribosomal DNA. The ITS gene region from the nuclear genomes were tested for their suitability as DNA barcoding regions of thirty-nine pepper individuals. Universal primers were used, and sequenced products were analyzed using the Maximum Likelihood method and Tamura-Nei model in the MEGA X program.Results: We did not observe high variability in intraspecific distance within the ITS_u1-4 gene region between individuals, ranged from 0.000 to 0.155 (mean = 0.033). The size of the gene region has fluctuated from 667 to 685 bp between different individuals with the percentage (G + C) contained in the ITS_u1-4 gene region was ranged from 54.776% to 60.805%, mean = 60.174%. The values of Fu’s Fs, D, Fu and Li’s D* and F* were negative as well (Fs = -0.209, D = -1.824; P < 0.05, D* = -1.205; not significant, P > 0.10 and F* = -1.699; not significant, 0.10 > P > 0.05), indicating an excess of recently derived haplotypes and suggesting that either population expansion or background selection has occurred. The value Strobeck’s S the obtained between individuals in a population is high (S = 0.684). The results of evolutionary relationships of taxa obtained 3 groups with the highest value of Fst is shown in the pairs of groups II and III (Fst = 0.151), and the lowest is in groups II and I (Fst = 0.015). All of the new sequences have been deposited in GeneBank under the following accession numbers MZ636718 to MZ636756.Conclusions: This database is an important resource for researchers working on Species of pepper in Vietnam and also provides a tool to create ITS_u1-4 databases for any given taxonomy.

Background: The DNA barcoding is currently an effective and widely used tool that enables rapid and accurate identification of plant species. Methods: DNA barcoding of 9 chloroplast genes (rbcL, matK, trnH-psbA, accD-psaI, ndhA, psbE-petL, Rpl32-trnL, trnW-psaJ, trnSGCU-trnGGCC) were used to provide the theoretical basis for species identification, genetic diversity analysis of lotus population collected in Thua Thien Hue province, Vietnam. Universal primers were used and sequence products were analyzed using the MEGA X program. Result: The results showed that high levels of haplotype diversity (Hd), ranging from 0.618-0.869 and low levels of nucleotide diversity (Pi), ranging from 0.180 × 10-3-3.280 × 10-3 base on a total of nine gene regions of chloroplast genome. The neutrality tests show an excess of rare nucleotide position variations in individuals’ white lotus and derived haplotypes recent expansion. While the evolution of the individuals in the pink lotus may have to decrease. The phylogenetic analyses indicated that combined sequences were not insufficient to make a difference to the DNA barcoding in the individual’s lotus of the N. nucifera species this is in the study. The standardized and accurate barcode information of lotus is provided for researchers. It lays the foundation for the conservation, evaluation, innovative utilization and protection of Nelumbonaceae germplasm resources.