Sesquiterpenoids longifolene

In 2009, a group of School of Pharmacy, Dali University, China examined the essential oil of Hypericum patulum stem extracts using gas chromatography-mass spectrometry (GC-MS) after the steam distillation. Among 72 peaks, 24 essential oils with about 79.50% of the total essential oils were confirmed. A monoterpenoid a-pinene (23)(18.14%) was most abimdant and followed by 2,4a,5,6,7,8-hexahydro-3,5,5,9-tetramethyl-,(/ )-l/7-benzocycloheptene (24) (13.64%), a sesquiterpenoid P-caiyophyllene (25) (9.41%) and a sesquiterpenoid longifolene (26) (6.23%) (Figure 6) [17]. 

Together with the monoterpenoid terpineol, the sesquiterpenoid longifolene has been characterized as one of the main components of the aroma of Chinese black... 

FIGURE 2 Sesquiterpenoid examples. Longifolene [3], xanthanolides [4], thapsigargins [5], and englerins [6]. 

Huneck and Klein (160) reported isolation and characterization of the essential oil obtained from seven Jungermanniales species and one Metzgeriales species. From Scapania undulata, (—)-longifolene (439) and (—)-longiborneol (443) were isolated and their structures established by comparison of their spectral data with those of authentic samples. This represented first isolation of terpenoids from the Hepaticae and of sesquiterpenoids antipodal to those found in higher plants. The presence of longifolene (439) and isolongifolene (440) in Scapania species was revealed by GC-MS analysis (314). 

Only a few sesquiterpenoids have been encountered in studies of lichens (3-caryophyllene, a-copaene, (3-elemene, farnesane, p-gurjunene, longifolene, a-muurolene, P-selinene, and thujopsene from Evernia prunastri 319) and fukinanolide A (bakkanolide A) from Cetraria islandica ((555). Abscisic acid (ABA) was detected in all 26 lichen species investigated (175). 

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