Seasonal Variability of a Caryophyllane Chemotype Essential Oil of Eugenia patrisii Vahl Occurring in the Brazilian Amazon.

Eugenia patrisii Vahl is a native and non-endemic myrtaceous species of the Brazilian Amazon. Due to few botanical and phytochemical reports of this species, the objective of the present work was to evaluate the seasonal variability of their leaf essential oils, performed by GC and GC-MS and chemometric analysis. The results indicated that the variation in oil yields (0.7 ± 0.1%) could be correlated with climatic conditions and rainy (R) and dry seasons (D). (E)-caryophyllene (R = 17.1% ± 16.0, D = 20.2% ± 17.7) and caryophyllene oxide (R = 30.1% ± 18.4, D = 14.1% ± 19.3) are the major constituents and did not display significant differences between the two seasons. However, statistically, a potential correlation between the main constituents of E. patrisii essential oil and the climatic parameters is possible. It was observed that the higher temperature and insolation rates and the lower humidity rate, which are characteristics of the dry season, lead to an increase in the (E)-caryophyllene contents, while lower temperature and insolation and higher humidity, which occur in the rainy season, lead to an increase in the caryophyllene oxide content. The knowledge of variations in the E. patrisii essential oil composition could help choose the best plant chemical profile for medicinal purposes.

Essentials Oils from Brazilian Eugenia and Syzygium Species and Their Biological Activities.

The Eugenia and Syzygium genera include approximately 1000 and 1800 species, respectively, and both belong to the Myrtaceae. Their species present economic and medicinal importance and pharmacological properties. Due to their chemical diversity and biological activity, we are reporting the essential oils of 48 species of these two genera, which grow in South America and found mainly in Brazil. Chemically, a total of 127 oil samples have been described and displayed a higher intraspecific and interspecific diversity for both Eugenia spp. and Syzygium spp., according to the site of collection or seasonality. The main volatile compounds were sesquiterpene hydrocarbons and oxygenated sesquiterpenes, mainly with caryophyllane and germacrane skeletons and monoterpenes of mostly the pinane type. The oils presented many biological activities, especially antimicrobial (antifungal and antibacterial), anticholinesterase, anticancer (breast, gastric, melanoma, prostate), antiprotozoal (Leishmania spp.), antioxidant, acaricidal, antinociceptive and anti-inflammatory. These studies can contribute to the rational and economic exploration of Eugenia and Syzygium species once they have been identified as potent natural and alternative sources to the production of new herbal medicines.

Seasonal and Antioxidant Evaluation of Essential Oil from Eugenia uniflora L., Curzerene-Rich, Thermally Produced in Situ.

The essential oil of Eugenia uniflora has been attributed anti-depressive, antinociceptive, antileishmanial, larvicidal, antioxidant, antibacterial, and antifungal activities. It is known that the cultivation of this plant can be affected by seasonality, promoting alteration in the oil composition and its biological activities. This study aims to perform the annual evaluation of the curzerene-type oil of E. uniflora and determine its antioxidant activity. The oil yield from the dry season (1.4 ± 0.6%) did not differ statistically from that of the rainy season (1.8 ± 0.8%). Curzerene, an oxygenated sesquiterpene, was the principal constituent, and its percentage showed no significant difference between the two periods: dry (42.7% ± 6.1) and rainy (40.8 ± 5.9%). Principal component and hierarchical cluster analyses presented a high level of similarity between the monthly samples of the oils. Also, in the annual study, the yield and composition of the oils did not present a significant correlation with the climatic variables. The antioxidant activity of the oils showed inhibition of DPPH radicals with an average value of 55.0 ± 6.6%. The high curzerene content in the monthly oils of E. uniflora suggests their potential for use as a future phytotherapeutic alternative.

Composition, antioxidant capacity and cytotoxic activity of Eugenia uniflora L. chemotype-oils from the Amazon.

ETHNOPHARMACOLOGICAL RELEVANCE: Oils and extracts of Eugenia uniflora have been reported as antimicrobial, antifungal, antinociceptive, antiprotozoal, antioxidant and cytotoxic. AIM OF THE STUDY: The oils of five specimens (E1 to E5) that occur in the Brazilian Amazon were extracted, analyzed for their chemical composition, and submitted to antioxidant and cytotoxic assays. MATERIAL AND METHODS: Oils were hydrodistilled, analyzed by GC and GC-MS, and submitted to PCA and HCA analyses. The antioxidant activity of the oils was evaluated by the DPPH radical scavenging and the ß-carotene/linoleic acid assays. Antiproliferative effects of the oils and curzerene were tested against colon (HCT-116), gastric (AGP-01), and melanoma (SKMEL-19) human cancer cell lines and a normal human fibroblast cell line (MRC-5), using MTT assay. RESULTS: Oxygenated sesquiterpenes and sesquiterpene hydrocarbons such as curzerene, selina-1,3,7(11)-trien-2-one, selina-1,3,7(11)-trien-2-one epoxide, germacrene B, caryophyllene oxide, and (E)-caryophyllene were predominant in the oils. PCA and HCA analyses classified the oils samples into four chemotypes. TEAC values of chemotype II (E3 oil, 228.3 ±â€¯19.2 mg TE/mL) and chemotype III (E4 oil, 217.0 ±â€¯23.3 mg TE/mL) displayed significant antioxidant activities. The oils E2 and E4 showed cytotoxic activity against all cell lines tested HCT-116 (IC50 E2:16.26 µg/mL; IC50 E4:9.28 µg/mL), AGP-01, (IC50 E2:12.60 µg/mL; IC50 E4:8.73 µg/mL), SKMEL-19 (IC50 E2:12.20 µg/mL; IC50 E4:15.42 µg/mL), and MRC-5 (IC50 E2:10.27 µg/mL; IC50 E4:14.95 µg/mL). Curzerene showed the more significant activity against melanoma cells (SKMEL-19, IC50:5.17 µM), induced apoptosis at 5.0 µM and 10.0 µM compared to DMSO, exhibiting a decrease in the cell migration at 5.0 µM and 10.0 µM, after 30 h of treatment. CONCLUSION: The curzerene chemotype oil and E. uniflora oils can be indicated as drug candidates for anticancer activity of the lung, colon, stomach, and melanoma, with a real prospect to their subsequent phytotherapeutic development.