Medicinal plant resin natural products: structural diversity and biological activities.

Covering: up to the mid of 2023Plants secrete defense resins rich in small-molecule natural products under abiotic and biotic stresses. This comprehensive review encompasses the literature published up to mid-2023 on medicinal plant resin natural products from six main contributor genera, featuring 275 citations that refer to 1115 structurally diverse compounds. The scope of this review extends to include essential information such as the racemic nature of metabolites found in different species of plant resins, source of resins, and revised structures.

Mantidisflavin A: A Riboflavin Derivative Featuring a 6/6/6/5/5 Skeleton from the Egg Cases of the Insect Saussure and Its Anti-Renal Fibrosis Activity.

Mantidisflavin A () was isolated from the egg cases of the Saussure. It exhibits an unprecedented 6/6/6/5/5 skeleton, accompanied by the formation of two additional fused heterocycles through a novel C-C bond and an oxygen bridge on riboflavin backbone. The structure of was identified by spectroscopic and computational methods.

X-ray Study of Cembranoids with Flexible Rings from Boswellia papyrifera Resins Allowing Structural Revision of Misleading Structures from the Past 70 Years.

Thirty new, highly oxygenated and stereogenic 14-membered macrocyclic diterpenoids, papyrifuranols A-Z (1-26) and AA-AD (27-30), and eight known analogs have been isolated from Boswellia papyrifera resins. All the structures were characterized by detailed spectral analyses, quantum calculations, X-ray diffraction, and modified Mosher's methods. Notably, six previously reported structures were revised.

COX-2 and iNOS inhibitory epimeric meroterpenoids from Ganoderma cochlear and structure revision of cochlearol Q.

Four novel epimeric meroterpenoids, ganadone A (1), 3',10'-di-epi-ganadone A (2), 10'-epi-ganadone A (3), and 3'-epi-ganadone A (4) as well as another pairs of epimers, ganadone B (5) and 10'-epi-ganadone B (6), with a same basic skeleton compound ganadone C (7), together with two lactonized meroterpenoids, ganadones D and E (8 and 9) were isolated from the fruiting bodies of Ganoderma cochlear. Compounds 1-7 were constructed with fascinating adjacent 6',7'-bifuran ring system. Fortunately, we have revised our previously reported structure cochlearol Q, which was proposed pyrano[6',7'-b]pyran ring system into 6',7'-bifuran motif.

Liquidambarines A - C, three new abietane diterpenoids from Hance and their anti-inflammatory activities.

Liquidambarines A - C (-), three new abietane-type diterpenoids, together with five known compounds (-) were isolated from the resin of Hance. Their structures were elucidated by the combination of spectroscopic and computational methods. We explored their anti-inflammatory potential by analyzing the protein expression of iNOS and COX-2.

Click linker: efficient and high yielding synthesis of a new family of kojic acid congeners as cytotoxic agents.

Highly efficient methodology was developed for the construction of functionalized Kojic acid involving Click linker via 1,3-dipolar cycloaddition and their cytotoxicity against MCF-7, MIAPaCa-2 and DU145 mammalian cell lines were evaluated. Preliminary studies on structure-activity-relationship (SAR) revealed that substitution at C-2 of kojic acid as well as C-5 of 1,2,3-triazole motif played a major role in the activity profile. Kojic acid 1,2,3-triazole analogue containing an alkyl chain ( = 6) exhibited two fold potent activity than the parent compound, kojic acid against MCF-7 and MIA PaCa-2 cell lines.

Biotransformation of Artemisinin to 14-Hydroxydeoxyartemisinin: C-14 Hydroxylation by Aspergillus flavus.

The biotransformation of the front-line antimalarial drug, artemisinin (1) by the filamentous fungus Aspergillus flavus MTCC-9167 was investigated. Incubation of compound 1 with A. flavus afforded a new hydroxy derivative (2) along with three known metabolites (3-5).

Self gelating isoracemosol A, new racemosaceramide A, and racemosol E from Barringtonia racemosa.

Phytochemical investigation into the CHCl extract of the fruits of Barringtonia racemosa resulted in the isolation of two new metabolites along with isoracemosol A and betulinic acid as known metabolites. The new compounds were characterised as phytosphingosine-type ceramide [(2S,3S,4R)-2-[(2R)-2-hydroxyhexadecanoyl amino]-hexacos-8(E)-ene-1,3,4-triol, 1] and racemosol E [21β-acetoxy-22α-(2-methylbutyroxy)-olean-12-ene-3β,16α,28-triol, 2] on the basis of extensive spectroscopic data analysis and chemical modifications. In addition, the self-gelating property of isoracemosol A (3) was investigated for the first time, which leads to the unexpected agglomerated porous-like morphology.

Epimeric Excolides from the Stems of Excoecaria agallocha and Structural Revision of Rhizophorin A.

Excolides A-B (1-4) represent the first examples of a new class of secolabdanoids with an unprecedented framework, which were isolated from the stems of Excoecaria agallocha. Their structures were determined by spectroscopic analysis, chemical modifications, CD, and single-crystal X-ray analysis (1 and 4) as excolide A (1), 11-epi-excolide A (2), 11,13-di-epi-excolide A (3), and excolide B (4). In addition, the structure of rhizophorin A (7), a novel bicyclic secolabdanoid, was revised as excolide A (1).

Biotransformation of agallochaexcoerin A by Aspergillus flavus.

Agallochaexcoerin A (1), a seco-manoyl oxide diterpenoid was metabolised by pathogenic fungus, Aspergillus flavus, in growth media to yield a new metabolite, termed agallochaexcoerin G (2). It was confirmed by using IR, UV, (1)H NMR and HR-ESI-MS techniques. This microbial bioconversion was achieved by unusual dehydration at C-4 position.