Clerodane diterpenes: sources, structures, and biological activities

Medicinal plants are a reservoir of biologically active compounds with therapeutic properties that over time have been reported and used by diverse groups of people for treatment of various diseases. This review covers 15 selected medicinal plants distributed in Myanmar, including Dalbergia cultrata, Eriosema chinense, Erythrina suberosa, Millettia pendula, Sesbania grandiflora, Tadehagi triquetrum, Andrographis echioides, Barleria cristata, Justicia gendarussa, Premna integrifolia, Vitex trifolia, Acacia pennata, Cassia auriculata, Croton oblongifolius and Glycomis pentaphylla. Investigation of the phytochemical constituents, biological and pharmacological activities of the selected medicinal plants is reported. This study aims at providing a collection of publications on the species of selected medicinal plants in Myanmar along with a critical review of the literature data. As a country, Myanmar appears to be a source of traditional drugs that have not yet been scientifically investigated. This review will be support for further investigations on the pharmacological activity of medicinal plant species in Myanmar.

A Review on the Phytochemistry, Medicinal Properties and Pharmacological Activities of 15 Selected Myanmar Medicinal Plants

A desymmetrization strategy was developed involving iridium-catalyzed allylic dearomatization of indoles. The six-membered-ring spiroindolenines contain three contiguous stereogenic centers, including an all-carbon quaternary center, and were obtained in up to 99 % yield with 99 % ee and >95:5 d.r. When treated with a catalytic amount of tosylic acid, six-membered spiroindolenine undergoes an unprecedented six-to-seven-membered ring expansion, affording the corresponding hexahydroazepino[4,5-b]indole.

Iridium-Catalyzed Asymmetric Allylic Dearomatization by a Desymmetrization Strategy.

Palladium-catalyzed asymmetric cycloadditions of vinylcyclopropanes and in situ formed unsaturated imines: construction of structurally and optically enriched spiroindolenines.

https://pubs.rsc.org/en/content/articlepdf/2016/np/c6np00059b

Diterpenoids of terrestrial origin

Eight new monoterpenoid indole alkaloids, alstoyunines A-H (1-8), along with 17 known analogues, were isolated from Alstonia yunnanensis. The structures of. the new alkaloids were established by means of extensive spectroscopic methods. Alstoyunines C (3), E (5), and F (6) showed selective inhibition of Cox-2 (>75%). Alstoyunine F (6) showed weak cytotoxicity against the human myeloid leukemia HL-60 (IC(50) = 3.89 mu M) and hepatocellular carcinoma SMMC-7721 (IC(50) = 21.73 mu M) cell lines.

Monoterpenoid Indole Alkaloids from Alstonia yunnanensis

Two new aporphine-type isoquinoline alkaloids, (+)-N-(methoxy-carbonyl)-N-norlauroscholtzine (1) and (+)-N-(methoxy-carbonyl)-N-norglaucine (2), were isolated from Litsea cubeba and identified by spectroscopic techniques (NMR, MS, UV, and IR). Their structures contain an N-(methoxycarbonyl) moiety, which has seldomly been found in the natural products of these analogs. Both compounds 1 and 2 showed no antibacterial activity against Staphylococcus aureus.

/pdf/two-new-isoquinoline-alkaloids-from-litsea-cubeba-4buns06vm3.pdf

Two New Isoquinoline Alkaloids from Litsea cubeba

Two new clerodane-type diterpenoids, along with seven known compounds have been isolated from the aerial parts of Gomphostemma microdon. All structures were established on the basis of spectroscopic analyses, including application of MS, UV, IR, 1D and 2D NMR techniques.

/pdf/two-new-clerodane-type-diterpenoids-from-gomphostemma-207mz4sv65.pdf

Two New Clerodane-type Diterpenoids from Gomphostemma microdon

Four new isoflavanones with isoprenoid units, named triquetrumones E-H (1–4), were isolated from the whole plants of Tadehagi triquetrum. The structures were elucidated on the basis of spectroscopic analyses, including application of MS, UV, IR, 1D and 2D NMR spectroscopic techniques. 
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https://link.springer.com/content/pdf/10.1007%2Fs13659-011-0033-5.pdf

Rong-Ting Zhang

Papers

Monoterpenoid Indole Alkaloids from Alstonia yunnanensis

Two New Isoquinoline Alkaloids from Litsea cubeba

Two New Clerodane-type Diterpenoids from Gomphostemma microdon

Four new isoflavanones from Tadehagi triquetrum

Two New Isoquinoline Alkaloids from Litsea cubeba.