Chemical composition, antimicrobial and larvicidal activities of essential oils of two Syzygium species from Vietnam

Abstract

The present study is the first to investigate the chemical composition, antimicrobial and larvicidal activities of the essential oils from the leaves of Syzygium attopeuense (Gagnep.) Merr. & L.M.Perry and Syzygium tonkinense (Gagnep.) Merr. & L.M.Perry collected in Vietnam. The essential oils were extracted by hydrodistillation and analyzed by GC and GC–MS. The study indicated the presence of a high percentage of sesquiterpenes in both investigated essential oils. The major components of S. attopeuense essential oil were bicyclogermacrene (24.26%), (E)-caryophyllene (11.72%), and (E)-β-ocimene (6.75%), whereas S. tonkinense essential oil was dominated by (E)-caryophyllene (80.80%). The antimicrobial activity of essential oils was evaluated by broth microdilution assay to determine the minimum inhibitory concentration (MIC) and median inhibitory concentration (IC50). Both essential oils exhibited remarkable inhibitory activity against all tested Gram-positive bacteria and yeast than Gram-negative bacteria. Among them, essential oils of S. attopeuense and S. tonkinense possessed the strongest activity against Enterococcus faecalis (MIC = 4.00 μg/mL; IC50 = 1.69 μg/mL) and Candida albicans (MIC = 16.00 μg/mL; IC50 = 8.67 μg/mL), respectively. Furthermore, the larvicidal activity of essential oils was tested using fourth-instar larvae of Aedes aegypti. Results from the larvicidal test revealed that both essential oils had an excellent inhibitory effect against A. aegypti larvae with LC50 values from 25.55 to 30.18 μg/mL and LC90 values from 33.00 to 39.01 μg/mL. Our findings demonstrate that the essential oil extracted from S. attopeuense and S. tonkinense are potential sources of natural antimicrobials and can act as inexpensive mosquito larvicidal agents.

Essential Oils ofDistichochlamys benenica: Chemical Constituents, Mosquito Larvicidal and Antimicrobial Activities

“…The determination of MIC and IC 50 values was conducted using the previously described broth microdilution susceptibility method. 67 The bacteria were cultured in Mueller-Hinton broth, whereas the yeast was grown in Sabouraud broth.…”

“…Dog biscuits and yeast powder were combined in a 3:1 weight ratio to feed the larvae. The mosquito larvicidal activity of the EOs extracted from the leaves and rhizomes of D. benenica was tested based on the method previously described by Huong et al 67 Briefly, EOs dissolved in 1% ethanol (EtOH) were placed in a 500-mL container and added to water containing 20 larvae at the third and early fourth instar stage. The experiments took place at a temperature of 25 ± 2 °C.…”

Undescribed Phenolic Glycosides from Syzygium attopeuense and Their Inhibition of Nitric Oxide Production

“…S. attopeuense fruits are edible [2,3] . The main chemical components of the essential oil of S. attopeuense leaves were bicyclogermacrene, ( E )‐caryophyllene, and ( E )‐ β ‐ocimene [6] . However, so far there has not been any study on the other chemical composition of this plant as well as its biological activities.…”

“…[2,3] The main chemical components of the essential oil of S. attopeuense leaves were bicyclogermacrene, (E)-caryophyllene, and (E)-β-ocimene. [6] However, so far there has not been any study on the other chemical composition of this plant as well as its biological activities. Continuing studies looking for anti-inflammatory compounds from the genus Syzygium, [7,8] the MeOH extract of S. attopeuense leaves significantly exhibited NO production inhibition (percent inhibition reached 65 % at a concentration of 100 μg/mL).…”