The root of Rumex crispus L. has been shown to possess anti-gout and anti-diabetic properties, but the compounds responsible for these pharmaceutical effects have not yet been reported. In this study, we aimed to isolate and purify active components from the root of R. crispus, and to evaluate their anti-radical, anti-gout and anti-diabetic capacities. From the ethyl acetate (EtOAc) extract, two compounds, chrysophanol (1) and physcion (2), were isolated by column chromatography with an elution of hexane and EtOAc at a 9:1 ratio. Their structures were identified by spectrometric techniques including gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS), X-ray diffraction analyses and nuclear magnetic resonance (NMR). The results of bioassays indicated that (1) showed stronger activities than (2). For antioxidant activity, (1) and (2) exhibited remarkable DPPH radical scavenging capacity (IC₅₀ = 9.8 and 12.1 µg/mL), which was about two times stronger than BHT (IC₅₀ = 19.4 µg/mL). The anti-gout property of (1) and (2) were comparable to the positive control allopurinol, these compounds exerted strong inhibition against the activity of xanthine oxidase (IC₅₀ = 36.4 and 45.0 µg/mL, respectively). In the anti-diabetic assay, (1) and (2) displayed considerable inhibitory ability on α-glucosidase, their IC₅₀ values (IC₅₀ = 20.1 and 18.9 µg/mL, respectively) were higher than that of standard acarbose (IC₅₀ = 143.4 µg/mL). Findings of this study highlight that (1) and (2) may be promising agents to treat gout and diabetes, which may greatly contribute to the medicinal properties of Rumex crispus root.

Mosquito-borne infectious diseases are a persistent problem in tropical regions of the world, including Southeast Asia. Vector control has relied principally on synthetic insecticides, but these have detrimental environmental effects and there is an increasing demand for plant-based agents to control insect pests. Invasive weedy plant species may be able to serve as readily available sources of essential oils, some of which may be useful as larvicidal agents for control of mosquito populations. We hypothesize that members of the genus Conyza (Asteraceae) may produce essential oils that may have mosquito larvicidal properties. The essential oils from the aerial parts of Conyza bonariensis, C. canadensis, and C. sumatrensis were obtained by hydrodistillation, analyzed by gas chromatography–mass spectrometry, and screened for mosquito larvicidal activity against Aedes aegypti, Ae. albopictus and Culex quinquefasciatus. The essential oils of C. canadensis and C. sumatrensis, both rich in limonene (41.5% and 25.5%, respectively), showed notable larvicidal activities against Ae. aegypti (24-h LC₅₀ = 9.80 and 21.7 μg/mL, respectively) and Ae. albopictus (24-h LC₅₀ = 18.0 and 19.1 μg/mL, respectively). These two Conyza species may, therefore, serve as sources for alternative, environmentally-benign larvicidal control agents.

Two new compounds, named eudesm-4(15),7-diene-3α,9β,11-triol (1) and eudesm-4(15),7-diene-1β,3α,9β,11-tetraol (2) together with three known sesquiterpene lactones (1S,5R,7R,10R)-secoatractylolactone (3), (1S,5R,7R,10R)-secoatractylolactone-11-O-β-D-glucopyranoside (4) atractylenolide III (5) were isolated from the rhizomes of Atractylodes macrocephala. Their structures were elucidated by using 1D and 2D-NMR spectra and HRESIMS data. Compound 5 exhibited the most active anti-inflammatory activity with IC50 values of 27.5 μM in inhibiting of nitric oxide production. Compounds 1, 2, and 3 showed moderate effects while compound 4 was inactive.

Mosquitoes, in addition to being a biting nuisance, are vectors of several pathogenic viruses and parasites. As a continuation of our work identifying abundant and/or invasive plant species in Vietnam for use as ecologically friendly pesticidal agents, we obtained the essential oils of Blumea lacera, Blumea sinuata, Emilia sonchifolia, Parthenium hysterophorus, and Sphaeranthus africanus; analyzed the essential oils using gas chromatographic techniques; and screened the essential oils for mosquito larvicidal activity against Aedes aegypti and Aedes albopictus. The most active larvicidal essential oils were B. sinuata, which was rich in thymohydroquinone dimethyl ether (29.4%), (E)-β-caryophyllene (19.7%), α-pinene (8.8%), germacrene D (7.8%), and α-humulene (4.3%), (24-h LC₅₀ 23.4 and 29.1 μg/mL) on Ae. aegypti and Ae. albopictus, respectively, and Emilia sonchifolia, dominated by 1-undecene (41.9%) and germacrene D (11.0%), (24-h LC₅₀ 30.1 and 29.6 μg/mL) on the two mosquito species. The essential oils of P. hysterophorus and S. africanus were also active against mosquito larvae. Notably, B. sinuata, P. hysterophorus, and S. africanus essential oils were not toxic to the non-target water bug, Diplonychus rusticus. However, E. sonchifolia essential oil showed insecticidal activity (24-h LC₅₀ 48.1 μg/mL) on D. rusticus. Based on these results, B. sinuata, P. hysterophorus, and S. africanus essential oils appear promising for further investigations.

The chemical composition and anti-inflammatory activity of the endemic Lysimachia baviensis were investigated for the first time in this study. A phytochemical fractionation of the methanol extract of L. baviensis resulted in the isolation of a new stilbene (bavienside A, 1) and two new chalcone glycosides (baviensides B and C, 2 and 3). Their structures were elucidated via the interpretation of NMR and HRESIMS spectroscopic data. Compounds 1–3 strongly inhibited the production of nitric oxide in LPS-induced RAW264.7 cells with the IC₅₀ values of 6.23, 2.86 and 3.51 μM, respectively. The C-acetylstilbene and carbomethyl chalcone structures in compound 1 and 3 were found for the first time from natural source and could be important markers for chemotaxonomy of Lysimachia baviensis. Graphical Abstract

Phytochemical investigation of the alkaloid composition in Pandanus amaryllifolius Roxb. and Pandanus tectorius Parkinson was carried out. Nine pandane alkaloids were isolated and determined. The alkaloids pandamarilactonine B, N-acetylnorpandamarilactonine A and pandamarilactonine G were found for the first time in P. tectorius. The total alkaloid mixtures and alkaloid fractions of the species were evaluated for their anti-inflammatory activity using in vitro experimental models.