The essential oils (EOs) of the aerial parts of four Asarum species (A. geophilum, A. yentunensis, A. splendens and A. cordifolium) were isolated by steam distillation and analyzed by the GC/MS method. The A. cordifolium EO contains 33 constituents with the main component being elemicine (77.20%). The A. geophilum EO was contains 49 constituents with the main components being determined as 9-epi-(E)-caryophyllene (18.43%), eudesm-7(11)-en-4-ol (13.41%), β-caryophyllene (8.05%) and phytol (7.23%). The A. yentunensis EO contains 26 constituents with the main components being safrole (64.74%) and sesquicineole (15.34%). The EO of A. splendens contains 41 constituents with the main components being 9-epi-(E)-caryophyllene (15.76%), eudesm-7(11)-en-4-ol (14.21%), β-caryophyllene (9.52%) and trans-bicyclogermacrene (7.50%). For antimicrobial activity, the A. yentunensis EO exhibited the highest inhibition activity against Staphylococcus aureus and the A. cordifolium EO against Bacillus subtillis (MIC values of 100 μg/mL). For antioxidant activity, the A. geophilum EO showed the highest potential with an SC (%) value of 63.34 ± 1.0%, corresponding to an SC₅₀ value of 28.57 µg/mL. For anti-inflammatory activity, the A. splendens EO exhibited the highest potential with an IC₅₀ value of 21.68 µg/mL, corresponding to an inhibition rate of NO production of 69.58 ± 1.3% and the percentage of cell life was 81.85 ± 0.9%.

Essential oils (EOs) from the stem barks, leaf petioles, fruit petioles, fresh leaves, and fresh and dried fruits of Zanthoxylum rhetsa were extracted by hydrodistillation. The volatile compounds of the products were analyzed by gas chromatography (GC-FID) and gas chromatography/mass spectrometry (GC/MSD). Monoterpene hydrocarbons formed the predominant fraction of all six EO samples, of which sabinene is one of the major components (from 12.37 to 41.13). For the leaf petiole EO, limonene (25.01), sabinene (14.56), and linalool (12.63) are the major constituents, while the main constituents of fruit petiole EO were terpinolene (19.66), terpinen-4-ol (19.07), and sabinene (17.83). The major components of stem bark EO are terpinen-4-ol (18.23), sabinene (12.37), α-phellandrene (7.34), β-phellandrene (6.32), and γ-terpinene (6.12), while sabinene (38.35), terpinen-4-ol (13.71), γ-terpinene (6.47), and limonene (6.02) are the major constituents of fresh leaf EO. For the EOs of dried fruits and fresh fruits, sabinene, terpinolene, limonene, and terpinen-4-ol are the major constituents. The essential oils were also tested for their cytotoxic and antimicrobial activities. The results revealed that six EOs at concentrations of 50μg/mL exhibited inhibitory activity against at least one tested cancer cell line but were nontoxic on Vero normal cells. Most EOs showed moderate antimicrobial activity against F. oxysporum; however, there were no obvious activity against B. subtilis and S. aureus.

Four lignans, asarinin (1), horsfieldin (2), 5-(4-(3,4,5-trimethoxyphenyl)hexahydrofuro[3,4-c]furan-1-yl)benzo[d][1,3]dioxole (3), 5-(4-(3,5-dimethoxyphenyl)hexahydrofuro[3,4-c]furan-1-yl)benzo[d][1,3]dioxole (4), and four non-alkaloid compounds, piperonylic acid (5), hesperidin (6), syringin (7), and β-sitosterol (8) were isolated from the stem bark of Zanthoxylum rhetsa grown in Vietnam. Their chemical structures were elucidated by spectroscopic analysis and compared with the references. Except for compound 6, all the remaining compounds (1–5, 7, and 8) were isolated for the first time from Z. rhetsa. The isolated compounds were tested for their cytotoxic activity against three human cancer cell lines, LU-1, Hep-G2, and KB. Compound 5 showed moderate cytotoxic activity against all three cell lines with IC₅₀ values ranging from 48.13 to 49.06 µg mL⁻¹. Notably, compound 6 demonstrated selective cytotoxicity against LU-1, Hep-G2, and KB cancer cell lines (IC₅₀ 66.48–67.41 µg mL⁻¹) while non-toxic toward normal Vero cell. Compound 6 also exhibited its ability to inhibit main protease (M^pro) enzyme in vitro with an IC₅₀ value of 55.49 µg mL⁻¹ and in silico with the binding affinity toward targeted protein of −14.36 kcal mol⁻¹.