humulene and alpha-bergamotene

The profile and bioactivity of hops (Humulus lupulus L.) essential oil, a complex natural product extracted from cones via steam distillation, depends on genetic and environmental factors, and may also depend on extraction process. We hypothesized that compound mixtures eluted sequentially and captured at different timeframes during the steam distillation process of whole hop cones would have differential chemical and bioactivity profiles. The essential oil was collected sequentially at 8 distillation time (DT) intervals: 0-2, 2-5, 5-10, 10-30, 30-60, 60-120, 120-180, and 180-240 min. The control was a 4-h non-interrupted distillation. Nonlinear regression models described the DT and essential oil compounds relationship. Fractions yielded 0.035 to 0.313% essential oil, while control yielded 1.47%. The oil eluted during the first hour was 83.2%, 9.6% during the second hour, and only 7.2% during the second half of the distillation. Essential oil (EO) fractions had different chemical profile. Monoterpenes were eluted early, while sequiterpenes were eluted late. Myrcene and linalool were the highest in 0-2 min fraction, β-caryophyllene, β-copaene, β-farnesene, and α-humulene were highest in fractions from middle of distillation, whereas α- bergamotene, γ-muurolene, β- and α-selinene, γ- and δ-cadinene, caryophyllene oxide, humulne epoxide II, τ-cadinol, and 6-pentadecen-2-one were highest in 120-180 or 180-240 min fractions. The Gram-negative Escherichia coli was strongly inhibited by essential oil fractions from 2-5 min and 10-30 min, followed by oil fraction from 0-2 min. The strongest inhibition activity against Gram-negative Yersinia enterocolitica, and Gram-positive Clostridium perfringens, Enterococcus faecalis, and Staphylococcus aureus subs. aureus was observed with the control essential oil. This is the first study to describe significant activity of hops essential oils against Trypanosoma brucei, a parasitic protozoan that causes African trypanosomiasis (sleeping sickness in humans and nagana in other animals). Hops essential oil fractions or whole oil may be used as antimicrobial agents or for the development of new drugs.

Topics: Acyclic Monoterpenes; Alkenes; Antiprotozoal Agents; Bridged Bicyclo Compounds; Clostridium perfringens; Distillation; Drug Resistance, Bacterial; Enterococcus faecalis; Escherichia coli; Humulus; Monocyclic Sesquiterpenes; Monoterpenes; Oils, Volatile; Plant Extracts; Polycyclic Sesquiterpenes; Sesquiterpenes; Staphylococcus aureus; Steam; Trypanosoma brucei brucei; Yersinia enterocolitica

To study the volatile oil of Murraya exotica.. The volatile oil of Murraya exotica was extracted by steam-stilling and was identified by GC-MS-DS.. More than 90 compounds were separated, and 59 compounds were identified, accounting for 93.9% of the total essential oil of Murraya exotica. The major constituents of volatile oil were bicyclogermacrene (26.0%), beta-caryophyllene (20.8%), alpha-caryophyllene (5.8%), delta-cadinene (4.7%), spathulenol (4.3%), trans-alpha-bergamotene (4.1%), germacrene D (3.7%), beta-bisabolene (3.0%), ar-Curcumene (2.5%).. The major components of Murraya exotica are the terpenoids, including 80.6% of sesquiterpenoids and 11.9% of monoterpenoids. Bicyclogermacrene is identified in Murraya genus for the first time.

Topics: Bridged Bicyclo Compounds; Gas Chromatography-Mass Spectrometry; Monocyclic Sesquiterpenes; Murraya; Oils, Volatile; Plant Leaves; Plant Stems; Plants, Medicinal; Polycyclic Sesquiterpenes; Seasons; Sesquiterpenes; Sesquiterpenes, Germacrane