ChemInform Abstract: SYNTHESIS OF SOME 3‐OXYGENATED 5α‐TIRUCALLA‐7,24‐ AND ‐8,24‐DIENES

In the course of our ongoing search for new natural products as leads against protozoal diseases, the dichloromethane extract of Indian frankincense, the oleo-gum-resin obtained from , showed activity against . Bioactivity-guided fractionation led to the isolation of eight diterpenes: (1,3,7,11)-verticilla-3,7,12(18)-triene (), cembrene A (), serratol (), 1,3,7,811-7,8-epoxy-cembra-3,11-dien-1-ol (), incensole oxide (), (1,3,7,11,12)1,12-epoxy-4-methylenecembr-7-ene-3, 11-diol (), isoincensole oxide (), and isodecaryiol (). Furthermore, 10 triterpenes, namely, oleanolic acid (), 11-keto--boswellic acid (), 3-epi-neoilexonol (), uvaol (), -boswellic aldehyde (), 5-tirucalla-8,24-dien-3-ol (), isoflindissone lactone (), isoflindissol lactone (), (89,20)-tirucall-24-ene-3,20-diol (), and (320,24-epoxytirucalla-3,25-diol () as well as the sesquiterpene -bourbonene (), the monoterpene carvacrol () and the phenyl propanoids methyleugenol (), and p-methoxycinnamaldehyde () were isolated. All compounds were identified by mass spectrometry and nuclear magnetic resonance spectroscopic measurements. Compounds , and- are described for the first time. Compounds are isolated as natural products for the first time, compound for the first time from a plant. Antiplasmodial IC values and cytotoxicity against L6 rat skeletal myoblasts were determined. Isoflindissone lactone () was the most active compound with an IC of 2.2 µM against and a selectivity index of 18.

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“…13 C-NMR data are reported for the first time (▶ Table 2). 1 H-NMR data (▶ Table 3) are in agreement with published parts [27].…”

Section: Resultssupporting

confidence: 86%

“…Compound 14 was thus unambiguously assigned the depicted structure of 5α-tirucalla-8,24-dien-3α-ol. Boar et al obtained this compound by partial synthesis [27], but to the best of our knowledge it has not been described as a natural product before. 13 C-NMR data are reported for the first time (▶ Table 2).…”

Section: Resultsmentioning

confidence: 99%

Terpenoids from the Oleo-Gum-Resin of Boswellia serrata and Their Antiplasmodial Effects In Vitro

et al. 2017

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“…1 H and 13 C-NMR data were in complete agreement with those published [33,35,36]. Compound 1 was thus assigned the structure of 5α-tirucalla-8,24-dien-3α-acetate [37] obtained this compound by partial synthesis, while its hydroxyl analogs 5α-tirucalla-8,24-dien-3α-ol and 5α-tirucalla-7, 24-dien-3β-ol were previously published [33,38]. But, to the best knowledge, it has not been described as a natural product before.…”

Section: α-Glucosidase Inhibition and Structural-activity Relationshisupporting

confidence: 83%

Triterpenic Acids as Non-Competitive α-Glucosidase Inhibitors from Boswellia elongata with Structure-Activity Relationship: In Vitro and In Silico Studies

et al. 2020

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Fourteen triterpene acids, viz., three tirucallane-type (1–3), eight ursane-type (4–11), two oleanane-type (12, 13) and one lupane type (21), along with boswellic aldehyde (14), α-amyrine (15), epi-amyrine (16), straight chain acid (17), sesquiterpene (19) and two cembrane-type diterpenes (18, 20) were isolated, first time, from the methanol extract of Boswellia elongata resin. Compound (1) was isolated for first time as a natural product, while the remaining compounds (2‒21) were reported for first time from B. elongata. The structures of all compounds were confirmed by advanced spectroscopic techniques including mass spectrometry and also by comparison with the reported literature. Eight compounds (1–5, 11, 19 and 20) were further screened for in vitro α-glucosidase inhibitory activity. Compounds 3–5 and 11 showed significant activity against α-glucosidase with IC50 values ranging from 9.9–56.8 μM. Compound 4 (IC50 = 9.9 ± 0.48 μM) demonstrated higher inhibition followed by 11 (IC50 = 14.9 ± 1.31 μM), 5 (IC50 = 20.9 ± 0.05 μM) and 3 (IC50 = 56.8 ± 1.30 μM), indicating that carboxylic acid play a key role in α-glucosidase inhibition. Kinetics studies on the active compounds 3–5 and 11 were carried out to investigate their mechanism (mode of inhibition and dissociation constants Ki). All compounds were found to be non-competitive inhibitors with Ki values in the range of 7.05 ± 0.17–51.15 ± 0.25 µM. Moreover, in silico docking was performed to search the allosteric hotspot for ligand binding which is targeted by our active compounds investigates the binding mode of active compounds and it was identified that compounds preferentially bind in the allosteric binding sites of α-glucosidase. The results obtained from docking study suggested that the carboxylic group is responsible for their biologic activities. Furthermore, the α-glucosidase inhibitory potential of the active compounds is reported here for the first time.

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ChemInform Abstract: SYNTHESIS OF SOME 3‐OXYGENATED 5α‐TIRUCALLA‐7,24‐ AND ‐8,24‐DIENES

Abstract: Aus dem Ester (I) wird über die Stufen (IIa)‐(III) das 8,24‐Dienon Tirucallon (IV) dargestellt, dessen LiAlH4‐Reduktion das (III) isomere 8,24‐Dien‐3β‐ol (Tirucallol, Ausb. 77%) gibt.

Cited by 2 publications

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Terpenoids from the Oleo-Gum-Resin of Boswellia serrata and Their Antiplasmodial Effects In Vitro

Terpenoids from the Oleo-Gum-Resin of Boswellia serrata and Their Antiplasmodial Effects In Vitro

Triterpenic Acids as Non-Competitive α-Glucosidase Inhibitors from Boswellia elongata with Structure-Activity Relationship: In Vitro and In Silico Studies

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