Sphaeranthus africanus is commonly used as a traditional remedy for sore throats and pain treatment in Vietnam. The aerial parts have been studied for its anti-inflammatory and anti-proliferative properties. However, the antioxidant and antidiabetic potential of the plant has not been explored. In this work, hydrophilic extracts of the plant's aerial parts were prepared in order to investigate its antioxidant and anti-diabetic properties. Also, the cytotoxicity of the root was evaluated and compared to that of the aerial parts. All of the extracts inhibited lipid peroxidation with IC 50 values ranging from 2.05 to 3.56 µg/mL, indicating substantial antioxidant activity. At an IC 50 value of 4.80 μg/mL, the 50% ethanol extract exhibited the most potent inhibition of α-glucosidase. The cytotoxic activity of root extracts is 2 to 5-fold less than that of the aerial parts. Nevertheless, dichloromethane and ethyl acetate extracts of the root demonstrated a selective effect on leukemia cells, with no harm towards the normal HEK-293 cell line. This work provides a scientific support for the antioxidant and antidiabetic activity of the plant. Hence, it may find a promising material for the development of novel antioxidant and antidiabetic agents. More research can be conducted on the phytochemistry and anticancer activities of the plant’s root.

Aims: Endophytic bacteria (EB) living inside plant tissues possess different beneficial traits including siderophore production and other plant growth-promoting (PGP) activities. Siderophore-producing EB promote host plant growth by secreting ferrum in iron-deficient conditions. This study screened 19 siderophore producers in vitro, isolated from upland rice roots grown in mountain farms of Tung Village, Nậm Có Commune, Mù Cang Chải District, Yên Bái Province, Vietnam, for PGP traits, including phosphate solubilisation, indole-3-acetic acid (IAA), ammonia, gelatinase, amylase and catalase production. Methodology and results: The bacteria were identified by Matrix assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF MS). All 19 isolates were identified as genera Pseudomonas, Enterobacter, Pantoe, Bacillus, Burkholderia, Staphylococcus, Ralstonia and Cronotacter. The isolates produced catalase and ammonia. The amount of ammonia ranged from 60.74 ± 0.14 to 466.72 ± 0.18 mg/L. Out of the 19 siderophore producers, 17 (89.47%) were able to solubilise phosphate with solubilisation index (PSI) ranging from 1.12 ± 0.07 to 2.14 ± 0.15. The qualitative assays identified 12 isolates (63.15%) positive for IAA production with a tryptophan concentration of 5 mM, whereas 15 (78.94%) and 17 (89.47%) isolates were positive for gelatin and starch hydrolysis, respectively. Especially, 7 isolates were found to be positive for all tested assays in vitro including Pseudomonas rhodesiae (NC2), Enterobacter asburiae (NC50), Pantoea ananatis (NC63), Bacillus cereus (NC64), Burkholderia cenocepacia (NC110), Staphylococcus sciuri (NC112) and Ralstonia pickettii (NC122). Conclusion, significance and impact of study This study serves as crucial findings of multi-trait plant growth-promoting endophytic bacteria isolated from upland rice root in north-western Vietnam. The seven potential isolates positive for all tested assays could be effective PGP bacteria for bio-inoculants.
Oryza--microbiology ; Siderophores ; Plant Growth Regulators ; Vietnam