Leaf essential oils of the genusLeptospermum (Myrtaceae) in eastern Australia, Part 6.Leptospermum polygalifolium and allies

Abstract

The leaf essential oils of Leptospermum polygalifolium and related species were isolated and examined. L. morrisonlii produced an essential oil in which the principal component was the β‐triketone grandiflorone, while in L. oreophilum the principal component was (E,E)‐farnesol. L. variabile gave oils with a spread of composition, the majority of samples being rich in geranyl acetate, β‐caryophyllene and humulene, while another sample was rich in 1,8‐cineole and a further sample contained comparable amounts of α‐pinene, β‐caryophyllene and α‐, β‐ and γ‐eudesmol. Leptospermum sp. (Mt Maroon, A.R. Bean 6665) appeared to be a chemically variable species; one specimen showed β‐caryophyllene and humulene as principal components, while a second gave an oil rich in sesquiterpenes with β‐caryophyllene, δ‐cadinene, calamenene and an unidentified sesquiterpene hydrocarbon being the major contributors. Of the seven subspecies of L. polygalifolium, ssp. polygalifolium, montanum and howense contained oils which were rich in α‐, β, and γ‐eudesmol. These were the only subspecies to contain these compounds in more than trace amounts. Of the remaining four subspecies, ssp. cismontanum, transmontanum, tropicum and ‘wallum’, all contained significant amounts of 1,8‐cineole. They usually contained larger quantities of spathulenol. All seven subspecies contained α‐pinene in significant amounts, while all but spp. howense also contained β‐pinene, usually in comparable amounts. Leptospermum madidum spp. sativum gave an oil rich in monoterpenes, with α‐pinene, β‐pinene, and γ‐terpinene being the major components. α‐, β‐, and γ‐eudesmol also made significant contributions to the oil. Copyright © 2000 John Wiley & Sons, Ltd.

Essential oils from Leptospermums of the Sunshine Coast and Northern Rivers Regions

“…Like previous studies [ 3 ], two extremes in chemical composition were identified in the L. liversidgei species in this work: chemotype I high in isopulegol (15–33%) and citronellal (19–44%); chemotype II high in neral (21%) and geranial (31%). The monoterpenoid nature of L. polygalifolium wallum observed in this study (α-pinene, 5–32%, β-pinene, 0–7% and 1,8-cineole, 4–13%) was consistent with prior work [ 4 ], as was their low concentration of sesquiterpene alcohols (α-eudesmol, 0–3%, β-eudesmol, 0–5% and γ-eudesmol, 0–3%). Like previous studies [ 2 ], the predominance of monoterpenes (α-pinene, 26–43%, β-pinene, 1–7%) in L. semibaccatum chemotype II and its significant amounts of globulol, 2–3%, spathulenol, 3–4%, α-cadinol, 3–7% and α-muurolol, 0.7–2%, were observed in this work.…”

“…The percentage oil yield of L. laevigatum observed in this study (0.01–0.06%) was lower than found by Brophy and co-workers (0.1%) [ 2 ]. The range of percentage oil yield of L. polygalifolium wallum observed in this study (0.03–0.5%) was in the lower end of the range previously reported (0.2–0.8%) [ 4 ]. Both the L. liversidgei chemotypes examined in this study had percentage oil yields (I - 0.5–1% and II - 0.5%) consistent with the non-chemotype specific L. liversidgei range of oil yield found by Brophy and co-workers (0.3–2.7%) [ 3 ].…”

Essential oils from Leptospermums of the Sunshine Coast and Northern Rivers Regions

“…Like previous studies [ 3 ], two extremes in chemical composition were identified in the L. liversidgei species in this work: chemotype I high in isopulegol (15–33%) and citronellal (19–44%); chemotype II high in neral (21%) and geranial (31%). The monoterpenoid nature of L. polygalifolium wallum observed in this study (α-pinene, 5–32%, β-pinene, 0–7% and 1,8-cineole, 4–13%) was consistent with prior work [ 4 ], as was their low concentration of sesquiterpene alcohols (α-eudesmol, 0–3%, β-eudesmol, 0–5% and γ-eudesmol, 0–3%). Like previous studies [ 2 ], the predominance of monoterpenes (α-pinene, 26–43%, β-pinene, 1–7%) in L. semibaccatum chemotype II and its significant amounts of globulol, 2–3%, spathulenol, 3–4%, α-cadinol, 3–7% and α-muurolol, 0.7–2%, were observed in this work.…”

“…The percentage oil yield of L. laevigatum observed in this study (0.01–0.06%) was lower than found by Brophy and co-workers (0.1%) [ 2 ]. The range of percentage oil yield of L. polygalifolium wallum observed in this study (0.03–0.5%) was in the lower end of the range previously reported (0.2–0.8%) [ 4 ]. Both the L. liversidgei chemotypes examined in this study had percentage oil yields (I - 0.5–1% and II - 0.5%) consistent with the non-chemotype specific L. liversidgei range of oil yield found by Brophy and co-workers (0.3–2.7%) [ 3 ].…”

β-Triketone Inhibitors of Plant p-Hydroxyphenylpyruvate Dioxygenase: Modeling and Comparative Molecular Field Analysis of Their Interactions

“…CoMFA maps identified that the presence of bulky substituents on the ring structure had a negative impact on the activity of the compounds (yellow surfaces in Figure 4A). This is consistent with the observation that the volume of the binding domain can accommodate the β-triketones from the tetramethyl homologous series, but it is not large enough for triketones decorated with bulkier side chains (17)(18)(19).…”

Herbicidal β‐triketones are compartmentalized in leaves of Leptospermum species: localization by Raman microscopy and rapid screening

“…The leaves of L. morrisonii contain high concentrations of grandiflorone 1 (25–64% of hydrodistilled oils by GC‐FID) with no other β‐triketones detected (Brophy et al ., ), which made this species a good starting point for our investigation of β‐triketone localization in Leptospermum oil glands. The basal surface of a fresh leaf, c .…”

“…Brophy et al . () produced an essential oil with 58% grandiflorone 1 from L. morrisonii leaf, but their method employed recycling hydrodistillation with solvent extraction, and the time taken was not specified.…”

Essential oils from Leptospermums of the Sunshine Coast and Northern Rivers Regions

“…Like previous studies [ 3 ], two extremes in chemical composition were identified in the L. liversidgei species in this work: chemotype I high in isopulegol (15–33%) and citronellal (19–44%); chemotype II high in neral (21%) and geranial (31%). The monoterpenoid nature of L. polygalifolium wallum observed in this study (α-pinene, 5–32%, β-pinene, 0–7% and 1,8-cineole, 4–13%) was consistent with prior work [ 4 ], as was their low concentration of sesquiterpene alcohols (α-eudesmol, 0–3%, β-eudesmol, 0–5% and γ-eudesmol, 0–3%). Like previous studies [ 2 ], the predominance of monoterpenes (α-pinene, 26–43%, β-pinene, 1–7%) in L. semibaccatum chemotype II and its significant amounts of globulol, 2–3%, spathulenol, 3–4%, α-cadinol, 3–7% and α-muurolol, 0.7–2%, were observed in this work.…”

“…The percentage oil yield of L. laevigatum observed in this study (0.01–0.06%) was lower than found by Brophy and co-workers (0.1%) [ 2 ]. The range of percentage oil yield of L. polygalifolium wallum observed in this study (0.03–0.5%) was in the lower end of the range previously reported (0.2–0.8%) [ 4 ]. Both the L. liversidgei chemotypes examined in this study had percentage oil yields (I - 0.5–1% and II - 0.5%) consistent with the non-chemotype specific L. liversidgei range of oil yield found by Brophy and co-workers (0.3–2.7%) [ 3 ].…”

β-Triketone Inhibitors of Plant p-Hydroxyphenylpyruvate Dioxygenase: Modeling and Comparative Molecular Field Analysis of Their Interactions

“…CoMFA maps identified that the presence of bulky substituents on the ring structure had a negative impact on the activity of the compounds (yellow surfaces in Figure 4A). This is consistent with the observation that the volume of the binding domain can accommodate the β-triketones from the tetramethyl homologous series, but it is not large enough for triketones decorated with bulkier side chains (17)(18)(19).…”

Herbicidal β‐triketones are compartmentalized in leaves of Leptospermum species: localization by Raman microscopy and rapid screening

“…The leaves of L. morrisonii contain high concentrations of grandiflorone 1 (25–64% of hydrodistilled oils by GC‐FID) with no other β‐triketones detected (Brophy et al ., ), which made this species a good starting point for our investigation of β‐triketone localization in Leptospermum oil glands. The basal surface of a fresh leaf, c .…”

“…Brophy et al . () produced an essential oil with 58% grandiflorone 1 from L. morrisonii leaf, but their method employed recycling hydrodistillation with solvent extraction, and the time taken was not specified.…”

Essential oils from Leptospermums of the Sunshine Coast and Northern Rivers Regions

“…Like previous studies [ 3 ], two extremes in chemical composition were identified in the L. liversidgei species in this work: chemotype I high in isopulegol (15–33%) and citronellal (19–44%); chemotype II high in neral (21%) and geranial (31%). The monoterpenoid nature of L. polygalifolium wallum observed in this study (α-pinene, 5–32%, β-pinene, 0–7% and 1,8-cineole, 4–13%) was consistent with prior work [ 4 ], as was their low concentration of sesquiterpene alcohols (α-eudesmol, 0–3%, β-eudesmol, 0–5% and γ-eudesmol, 0–3%). Like previous studies [ 2 ], the predominance of monoterpenes (α-pinene, 26–43%, β-pinene, 1–7%) in L. semibaccatum chemotype II and its significant amounts of globulol, 2–3%, spathulenol, 3–4%, α-cadinol, 3–7% and α-muurolol, 0.7–2%, were observed in this work.…”

“…The percentage oil yield of L. laevigatum observed in this study (0.01–0.06%) was lower than found by Brophy and co-workers (0.1%) [ 2 ]. The range of percentage oil yield of L. polygalifolium wallum observed in this study (0.03–0.5%) was in the lower end of the range previously reported (0.2–0.8%) [ 4 ]. Both the L. liversidgei chemotypes examined in this study had percentage oil yields (I - 0.5–1% and II - 0.5%) consistent with the non-chemotype specific L. liversidgei range of oil yield found by Brophy and co-workers (0.3–2.7%) [ 3 ].…”

β-Triketone Inhibitors of Plant p-Hydroxyphenylpyruvate Dioxygenase: Modeling and Comparative Molecular Field Analysis of Their Interactions

“…CoMFA maps identified that the presence of bulky substituents on the ring structure had a negative impact on the activity of the compounds (yellow surfaces in Figure 4A). This is consistent with the observation that the volume of the binding domain can accommodate the β-triketones from the tetramethyl homologous series, but it is not large enough for triketones decorated with bulkier side chains (17)(18)(19).…”

Herbicidal β‐triketones are compartmentalized in leaves of Leptospermum species: localization by Raman microscopy and rapid screening

“…The leaves of L. morrisonii contain high concentrations of grandiflorone 1 (25–64% of hydrodistilled oils by GC‐FID) with no other β‐triketones detected (Brophy et al ., ), which made this species a good starting point for our investigation of β‐triketone localization in Leptospermum oil glands. The basal surface of a fresh leaf, c .…”

“…Brophy et al . () produced an essential oil with 58% grandiflorone 1 from L. morrisonii leaf, but their method employed recycling hydrodistillation with solvent extraction, and the time taken was not specified.…”