This study was conducted to examine the chemical constituents of Origanum majorana L. essential oils (EOs) that originate in Nepal, as well as their biological activities, antioxidant properties, and enantiomeric compositions. The EOs were extracted by the hydro-distillation method using a Clevenger-type apparatus and their chemical compositions were determined through gas chromatography and mass spectrometry (GC-MS). Chiral GC-MS was used to evaluate the enantiomeric compositions of EOs. The minimum inhibitory concentrations (MICs) of the essential oils were determined by the micro-broth dilution method, and the antioxidant activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl scavenging assay and ferric-reducing antioxidant power (FRAP). GC-MS analysis showed the presence of 50 and 41 compounds in the EO samples, (S₁) and (S₂), respectively, representing the Kathmandu and Bhaktapur districts. The oxygenated monoterpenoids, along with terpinen-4-ol, were predominant constituents in both EO samples. However, the EOs from two locations showed some variations in their major components. The chiral terpenoids for two EO samples of marjoram have also been reported in this study in an elaborative way for the first time in accordance with the literature review. A hierarchical cluster analysis based on the compositions of EOs with 50 compositions reported in the literature revealed at least 5 different chemotypes of marjoram oil. The antioxidant activity for the sample (S₂) was found to be relatively moderate, with an IC₅₀ value of 225.61 ± 0.05 μg/mL and an EC₅₀ value of 372.72 ± 0.84 µg/mL, as compared to the standard used. Furthermore, with an MIC value of 78.1 µg/mL, the EO from sample (S₂) demonstrated effective antifungal activity against Aspergillus niger and Candida albicans. Moreover, both samples displayed considerable antimicrobial activity. The results suggest that EOs of Origanum majorana possess some noteworthy antimicrobial properties as well as antioxidant activity, and hence can be used as a natural preservative ingredient in the food and pharmaceutical industries.

The plants from the Ocimum genus, belonging to the Labiatae family, serve as important bioresources of essential oils (EOs) rich in biologically active secondary metabolites, widely used in medicine, food, and cosmetics. This study explored the volatile composition, enantiomeric distribution, and in vitro biological activities of EOs from three Ocimum species native to Nepal: O. tenuiflorum L., O. basilicum L., and O. americanum L. EOs were extracted via hydro-distillation and analyzed using gas chromatography–mass spectrometry (GC-MS) for chemical profiling and chiral GC-MS for enantiomeric composition. Hierarchical cluster analysis was performed for major chemotypes. Antioxidant activity was assessed using DPPH and ABTS assays. Antimicrobial efficacy was evaluated using the microbroth dilution method, and cytotoxicity was tested on NIH-3T3 (normal) and MCF-7 (breast cancer) cell lines via the Cell Counting Kit-8 assay. EO yield was highest in O. tenuiflorum (1.67 ± 0.13%) during autumn and lowest in O. americanum (0.35 ± 0.02%) during winter among all Ocimum spp. The major compounds identified in O. tenuiflorum were eugenol (32.15–34.95%), trans-β-elemene (29.08–32.85%), and β–caryophyllene (19.85–21.64%). In O. americanum, the major constituents included camphor (51.33–65.88%), linalool (9.72–9.91%), germacrene D (7.75–1.83%), and β–caryophyllene (6.35–3.97%). For O. basicilum, EO was mainly composed of methyl chavicol (62.16–64.42%) and linalool (26.92–27.05%). The oxygenated monoterpenes were a dominant class of terpenes in the EOs except for O. tenuiflorum (sesquiterpene hydrocarbon). A hierarchical cluster analysis based on the compositions of EOs revealed at least three different chemotypes in Ocimum species. Chiral GC-MS analysis revealed β-caryophyllene and germacrene D as enantiomerically pure, with linalool consistently dominant in its levorotatory form. O. tenuiflorum exhibited the strongest antimicrobial activity, particularly against Candida albicans, and showed notable anticancer activity against MCF-7 cells (IC₅₀ = 23.43 µg/mL), with lower toxicity to normal cells. It also demonstrated the highest antioxidant activity (DPPH IC₅₀ = 69.23 ± 0.10 µg/mL; ABTS IC₅₀ = 9.05 ± 0.24 µg/mL). The EOs from Ocimum species possess significant antioxidant, antimicrobial, and cytotoxic properties, especially O. tenuiflorum. These findings support their potential application as natural agents in medicine, food, and cosmetics, warranting further validation.

Background: Essential oils (EOs) are one of the most important groups of plant secondary metabolites responsible for their various biological activities. They also have wide applications as natural ingredients in many fields like the food, cosmetic, and medicine industries. This study was conducted to determine the chemical composition, enantiomeric distribution, and in-vitro biological activities of Elsholtzia strobilifera (Benth.) Benth. and E. blanda (Benth.) Benth. essential oils of Lamiaceae from Nepal. Methods: Essential oils obtained from hydro-distillation were analyzed by gas-chromatography mass-spectrometry (GC–MS) for their chemical constituents and the enantiomeric distribution of chiral terpenoids were determined by chiral GC–MS. Microbroth dilution was used to investigate the in-vitro antimicrobial activity, while cytotoxic activities were determined by cell viability using a Cell Counting Kit assay. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging and FRAP (ferric-reducing antioxidant power) assays were used to evaluate the antioxidant activities. Results: A total of 55 compounds were identified in E. strobilifera with pinocarvone (40.7%), β-pinene (10%) and cis-pinocamphone (7.9%) as predominant constituents. While, 41 compounds were identified in the E. blanda EOs, including dihydrotagetone (49.1%), ( Z)-tagetone (15.6%) and ( E)-tagetone (8%) as major components; both essential oils were dominated by oxygenated monoterpenoids. The chiral separation and analyses of 12, E. strobilifera and 7, E. blanda essential oil components were performed, respectively, where (–)-β-caryophyllene and (–)-germacrene D were detected as enantiomerically pure in both oils. Elsholtzia EOs exhibited strong antifungal activity with MIC value of 156.3 µg/mL against Aspergillus niger, whereas, E. strobilifera EO against Staphylococcus epidermidis and E. blanda EO against Staphylococcus aureus showed inhibitory effects with MIC values of 156.3 µg/mL. E. strobilifera EO showed very active in-vitro cytotoxicity against the NIH-3T3 cell line with IC₅₀ of 20.2 µg/mL, whereas E. blanda EO displayed effective cytotoxicity against MCF-7 cell line with IC₅₀ of 33.1 µg/mL. The antioxidant activity of E. strobilifera EO was relatively good with IC₅₀ of 188.8 ± 0.7 µg/mL in DPPH and EC₅₀ value of 348.0 ± 0.1 µg/mL in FRAP, as compared to that of E. blanda EO. Conclusion: Elsholtzia EOs showed prominent biological activities emphasizing their importance as natural ingredients.

There are an increasing number of studies on the cosmeceutical properties of medicinal plants growing in various climatic zones. The formulation of phenolic rich plant extracts into cosmetic cream products can maximize the commercial value of such products. Most of the herbs used in Nepal for cosmetic purposes are locally available Ayurvedic herbs. The antioxidant property of the ethanolic extracts of Moringa oleifera L. leaves collected from Rupandehi and Makawanpur districts respectively were determined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. Total phenolic and total tannin content was determined by Foline Ciocalteu reagent. Total phenolic content was found from 35.51 and 42.89 mg/100 g gallic acid in the Makawanpur and Rupandehi districts. Overall, findings revealed that there were slight differences in antioxidant properties between the two samples. The cream formulated from the Makawanpur plant sample had considerable physiochemical parameters within the range of acceptance. These findings provide strong evidence for further development of commercial creams with antioxidant properties

Perilla is widely valued for its culinary, aromatic, and medicinal uses. This study was conducted to characterize the chemical components, enantiomeric distribution, and to explore the antimicrobial, antioxidant, and cytotoxic potential of essential oils from Perilla frutescens L. found in Nepal. Essential oils (EOs) obtained through hydrodistillation were analyzed for their chemical constituents using gas chromatography-mass spectrometry (GC-MS), while chiral GC-MS was employed to determine the enantiomeric distribution of chiral terpenoids. The DPPH and ABTS radical-scavenging assays were used to evaluate the antioxidant activities. In vitro antimicrobial activity was performed by microbroth dilution. Cytotoxic activities were determined by cell viability using a Cell Counting Kit assay. GC-MS analyses of three P. frutescens (PEO) samples had 50 to 54 chemical components, consisting of 91.98 to 99.67 %. PEO was characterized as PK type by the most dominant components, perilla ketone (42.26 to 56.26 %), isoegomaketone (23.68-23.85 %), β-caryophyllene (1.33-7.33 %), and isobicyclogermacrene (3.29-5.27 %), respectively. Twelve chiral terpenoids were identified as enantiomeric distribution with 1-octen-3-ol (100 % as dextrorotatory) in all three PEO samples. PEO collected from Bardiya in summer gave the best antioxidant activity against DPPH with an IC50 value of 334.26±0.20 µg/mL and against ABTS with an IC50 value of 93.15±1.04 µg/mL. The antimicrobial inhibition against E. coli, C. albicans, and A. niger was observed, with MICs varying from 156.3 to 625 µg/mL. PEO taken from Kavre in summer showed good cytotoxicity with an IC50 value of 7.41 µg/mL against the NIH-3T3 cell line and an IC50 value of 8.14 µg/mL against the MCF-7 cell line. All three PEOs showed notable chemical complexity and promising biological activities, emphasizing their importance as natural ingredients.