Chemical Composition, and Evaluation of Antibacterial，Antibiofilm and Synergistic Effects with Conventional Antibiotics of Essential Oil from Mallotus repandus

The essential oil (EO) of aerial parts of Mallotus repandus (Willd.) Muell. Arg. was extracted by hydrodistillation and characterized by GC/FID and GC/MS. Fifty-one compounds comprising 97.1% of the EO were identified, of which α-humulene (18.7%), β-selinene (12.8%), aciphyllene (10.7%), (E)-caryophyllene (8.4%), α-copaene (5.5%), humulene epoxide II (4.9%) and caryophyllene oxide (4.3%) were the major compounds. The EO was evaluated for antibacterial properties using broth microdilution method and crystal-violet static biofilm formation assay. The M. repandus EO possessed a bactericidal effect against tested gram-positive bacteria strains (MIC = MBC: 0.05-0.10 mg/mL). Further, the EO showed the ability to inhibit the biofilm formation of Staphylococcus aureus. In addition, the potential synergistic effect was assessed by checkerboard method. Combination of the M. repandus EO with Streptomycin showed synergistic effects against the tested bacterial strains. This study demonstrates that M. repandus EO could be further explored as good alternative for potential pharmaceuticals.

Analgesic and Anti-Inflammatory Activities of Leaf Extract ofMallotus repandus(Willd.) Muell. Arg.

In folk medicineMallotus repandus(Willd.) Muell. Arg. is used to treat muscle pain, itching, fever, rheumatic arthritis, snake bite, hepatitis, and liver cirrhosis. This study aimed to evaluate the antinociceptive as well as the anti-inflammatory activities of the methanol extract of leaf. The leaves were extracted with methanol following hot extraction and tested for the presence of phytochemical constituents. Analgesic and anti-inflammatory activities were evaluated using acetic acid induced writhing test, xylene induced ear edema, cotton pellet induced granuloma, and tail immersion methods at doses of 500, 1000, and 2000 mg/kg body weight. The presence of flavonoids, saponins, and tannins was identified in the extract. The extract exhibited considerable antinociceptive and anti-inflammatory activities against four classical models of pain. In acetic acid induced writhing, xylene induced ear edema, and cotton pellet granuloma models, the extract revealed dose dependent activity. Additionally, it increased latency time in tail immersion model. It can be concluded thatM. repanduspossesses significant antinociceptive potential. These findings suggest that this plant can be used as a potential source of new antinociceptive and anti-inflammatory candidates. The activity of methanol extract is most likely mediated through central and peripheral inhibitory mechanisms. This study justified the traditional use of leaf part of this plant.

Studies on Taiwan Folk Medicine, Thang-kau-tin (II): Measurement of Active Oxygen Scavenging Activity Using an ESR Technique

Using an electron spin resonance (ESR) technique, we measured the superoxide radical (• O 2-) and hydroxyl radical (•OH) scavenging activity from Mallotus repandus (Willd.) Muell.-Arg., Bauhinia championii Benth., Uncaria hirsuta Haviland and Uncaria rhynchophylla Miquel. • O 2- and •OH were detected as spin adducts of spin traps 5,5-dimethylpyrroline-N-oxide (DMPO). The scavenging potencies of water extracts of crude drugs were evaluated in terms of their ability to reduce the peaks of spin adducts. The extract of B. championii showed the greatest superoxide radical and hydroxyl radical scavenger activity.