The extensive use of glyphosate (N-(phosphonomethyl) glycine) herbicide in agriculture is accompanied by the risk of environmental contamination of aquatic ecosystems. In this study, the effects of glyphosate at different concentrations (50–500 µg ml-1) on three Chlorella species including Chlorella ellipsoidea, Chlorella sorokiniana and Chlorella vulgaris especially in relation to the biomass, pigment contents and photosynthetic efficiency were assessed. After treatment for 24 hr, the acute toxicity results showed that C. vulgaris (IC50 = 449.34 ± 6.20 µg ml-1) was more tolerant to glyphosate than C. ellipsoidea (IC50 = 288.23 ± 23.53 µg ml-1) and C. sorokiniana (IC50 = 174.28 ± 0.50 µg ml-1). After a 72-hr chronic toxicity treatment with glyphosate, glyphosate concentrations decreased to 400–500 µg ml-1 in C. ellipsoidea, 200–300 µg ml-1 in C. sorokiniana and 200–500 µg ml-1 in C. vulgaris respectively. During 24-hr acute toxicity exposure to glyphosate, the pigment contents and maximum quantum efficiency of photosystem II (Fv/Fm) decreased as the concentration of glyphosate increased. Overall, the biomass, pigment contents and photosynthetic efficiency presented a high positive correlation. It is worthwhile to mention that our study provides detailed information on the toxicity and sensitivity of these Chlorella species to glyphosate.

Several plants of the Rubiaceae family possess potential pharmacological properties, such as antioxidant activity, for subsequent drug development. We investigated the methanolic extracts from the bark and wood of five Rubiaceae species for phenolic and flavonoid contents and antioxidant activity. Regarding the phytochemical contents and antioxidant activity, Mitragyna diversifolia wood (437.57 ± 9.90 mg GAE g-1) and Haldina cordifolia wood (30.11 ± 0.20 mg QE g-1) displayed the highest total phenolic content (TPC) and total flavonoid content (TFC) respectively. Morinda coreia bark followed the highest antioxidant activities (IC50 = 360.58 ± 19.28 µg ml-1) in the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), Catunaregam tomentosa bark (IC50 = 13.96 ± 5.32 µg ml-1) in the nitric oxide radical scavenging activity (NO), M. coreia wood (IC50 = 918.27 ± 0.16 µg ml-1) in the superoxide radical scavenging activity (SO) and M. coreia wood (IC50 = 236.65 ± 1.66 µg ml-1) in ferric reducing antioxidant power activity (FRAP). The TPC and TFC displayed strong correlations with DPPH in M. diversifolia wood and with FRAP in M. diversifolia bark and wood. We found high correlation between TFC and FRAP in all plant extracts except C. tomentosa wood, while no relation was detected between TFC and NO in all plant extracts. Comparing Rubiaceae species, the highest antioxidant potential were showed in C. tomentosa bark. Overall, it is worth mentioning that the Rubiaceae species exhibit potential as a promising source of natural antioxidants.

Commonly used to treat skin injuries in Asia, several Homalium spp. have been found to promote skin regeneration and wound healing. While ethnobotanical surveys report the use of H. bhamoense trunk bark as a wound salve, there are no studies covering bioactive properties. As impaired cutaneous healing is characterized by excessive inflammation, a series of inflammatory mediators involved in wound healing were targeted with a methanol extract obtained from H. bhamoense trunk bark. Results showed concentration-dependent inhibition of hyaluronidase and 5-lipoxygenase upon exposure to the extract, with IC₅₀ values of 396.9 ± 25.7 and 29.0 ± 2.3 µg mL⁻¹, respectively. H. bhamoense trunk bark extract also exerted anti-inflammatory activity by significantly suppressing the overproduction of interleukin 6 (IL-6) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages at concentrations ranging from 125 to 1000 µg mL⁻¹, while leading to a biphasic effect on nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) levels. The phenolic profile was elucidated by HPLC-DAD, being characterized by the occurrence of ellagic acid as the main constituent, in addition to a series of methylated derivatives, which might underlie the observed anti-inflammatory effects. Our findings provide in vitro data on anti-inflammatory ability of H. bhamoense trunk bark, disclosing also potential cutaneous toxicity as assessed in HaCaT keratinocytes.