cholinesterase. Based on the current results, H. flavum could be considered as a source of bioactive compounds and has high exploitation potential in the cosmetics, food, and pharmaceutical industries.

The chemical composition and biological activities of the essential oil from Ficus tikoua Bur. were reported for the first time. Fifty-three compounds, accounting for 99.60% of the total essential oil composition, were identified and the main components were palmitic acid (51.13%) and linoleic acid (47.54%). The essential oil revealed significant antibacterial activity with the inhibition zones (7.89-10.59 mm), MIC (0.20-6.25 mg/mL) and MBC (0.20-12.50 mg/mL) against Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Proteus vulgaris. The essential oil exhibited significant cytotoxicity against A549, NCI-H1299, PC-3 and K562 tumor cells with the IC50 values of 131.08, 50.32, 120.58 and 31.68 μg/mL, respectively. The essential oil exhibited selective cytotoxic activity to human tumor cell lines, with a significantly lower cytotoxicity to human normal cell line (MRC-5, IC50 = 161.75 μg/mL) than to tumor cells. Additionally, palmitic acid, as the major compound, aslo revealed significant antibacterial and cytotoxic activities.

Rhynchanthus beesianus W. W. Smith, an edible, medicinal, and ornamental plant, is mainly cultivated in China and Myanmar. The essential oil (EO) from R. beesianus rhizome has been used as an aromatic stomachic in China. The chemical composition and biological activities of EO from R. beesianus rhizome were reported for the first time. Based on gas chromatography with flame ionization or mass selective detection (GC-FID/MS) results, the major constituents of EO were 1,8-cineole (47.6%), borneol (15.0%), methyleugenol (11.2%), and bornyl formate (7.6%). For bioactivities, EO showed a significant antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Proteus vulgaris with the diameter of the inhibition zone (DIZ) (8.66–10.56 mm), minimal inhibitory concentration (MIC) (3.13–6.25 mg/mL), and minimal bactericidal concentration (MBC) (6.25–12.5 mg/mL). Moreover, EO (128 μg/mL) significantly inhibited the production of proinflammatory mediators nitric oxide (NO) (92.73 ± 1.50%) and cytokines tumor necrosis factor-α (TNF-α) (20.29 ± 0.17%) and interleukin-6 (IL-6) (61.08 ± 0.13%) in lipopolysaccharide (LPS)-induced RAW264.7 macrophages without any cytotoxic effect. Moreover, EO exhibited significant acetylcholinesterase (AChE) inhibitory activity (the concentration of the sample that affords a 50% inhibition in the assay (IC50) = 1.03 ± 0.18 mg/mL) and moderate α-glucosidase inhibition effect (IC50 = 11.60 ± 0.25 mg/mL). Thus, the EO could be regarded as a bioactive natural product and has a high exploitation potential in the cosmetics and pharmaceutical industries.

Rhynchanthus beesianus is a medicinal, ornamental, and edible plant, and its essential oil has been used as an aromatic stomachic in China. In this study, the chemical constituents, antibacterial, and anti-inflammatory properties of flower essential oil (F-EO), leaf essential oil (L-EO), and stem essential oil (S-EO) of R. beesianus were investigated for the first time. According to the GC-FID/MS assay, the F-EO was mainly composed of bornyl formate (21.7%), 1,8-cineole (21.6%), borneol (9.7%), methyleugenol (7.7%), β-myrcene (5.4%), limonene (4.7%), camphene (4.5%), linalool (3.4%), and α-pinene (3.1%). The predominant components of L-EO were bornyl formate (33.9%), borneol (13.2%), 1,8-cineole (12.1%), methyleugenol (8.0%), camphene (7.8%), bornyl acetate (6.2%), and α-pinene (4.3%). The main components of S-EO were borneol (22.5%), 1,8-cineole (21.3%), methyleugenol (14.6%), bornyl formate (11.6%), and bornyl acetate (3.9%). For the bioactivities, the F-EO, L-EO, and S-EO exhibited significant antibacterial property against Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, and Escherichia coli with the inhibition zones (7.28–9.69 mm), MIC (3.13–12.50 mg/mL), and MBC (6.25–12.50 mg/mL). Besides, the F-EO, L-EO, and S-EO significantly inhibited the production of proinflammatory mediator nitric oxide (NO) (93.15–94.72%) and cytokines interleukin-6 (IL-6) (23.99–77.81%) and tumor necrosis factor-α (TNF-α) (17.69–24.93%) in LPS-stimulated RAW264.7 cells at the dose of 128 μg/mL in the absence of cytotoxicity. Hence, the essential oils of R. beesianus flower, leaf, and stem could be used as natural antibacterial and anti-inflammatory agents with a high application potential in the pharmaceutical and cosmetic fields.