Antimalarial Eudesmane Sesquiterpenoids from Dobinea delavayi

Four new phenolic glycosides from Dobinea delavayi

Three new benzophenone glycosides, 2-O-β-D-glucopyranosyl-6,3',4'-trihydroxy-4-methoxybenzophenone (1), 4'-O-β-D-glucopyranosyl-2,4,6,3'-tetramethoxybenzophenone (2) and 2-O-β-D-glucopyranosyl-4'-hydroxy-6-methylbenzophenone (3), and a new flavonoid glycoside 5'-hydroxyombuoside (6), along with three known phenolic glycosides 4-O-β-D-glucopyranosyl-2,6,4'-trihydroxybenzophenone (4), mangiferin (5), and ombuoside (7), were isolated from the 80% ethanol extract of roots of Dobinea delavayi. Their structures were determined by the comprehensive analyses of the physicochemical properties and spectroscopic data (1D NMR, 2D NMR, and HR-ESI-MS). Cytotoxicity and in vitro antimalarial activity of compounds 1, 3, 4, 6, and 7 were evaluated by MTT colorimetric assay and β-hematin formation inhibition assay, respectively.

Potential candidates from marine and terrestrial resources targeting mitochondrial inhibition: Insights from the molecular approach

Mitochondria are the target sites for multiple disease manifestations, for which it is appealing to researchers' attention for advanced pharmacological interventions. Mitochondrial inhibitors from natural sources are of therapeutic interest due to their promising benefits on physiological complications. Mitochondrial complexes I, II, III, IV, and V are the most common sites for the induction of inhibition by drug candidates, henceforth alleviating the manifestations, prevalence, as well as severity of diseases. Though there are few therapeutic options currently available on the market. However, it is crucial to develop new candidates from natural resources, as mitochondria-targeting abnormalities are rising to a greater extent. Marine and terrestrial sources possess plenty of bioactive compounds that are appeared to be effective in this regard. Ample research investigations have been performed to appraise the potentiality of these compounds in terms of mitochondrial disorders. So, this review outlines the role of terrestrial and marine-derived compounds in mitochondrial inhibition as well as their clinical status too. Additionally, mitochondrial regulation and, therefore, the significance of mitochondrial inhibition by terrestrial and marine-derived compounds in drug discovery are also discussed.

Phloridzin Highly Accumulated in Malus rockii Rehder and Its Structure Revision and Hypolipidemic Activity

Phloridzin is a lead compound of the prestigious antidiabetic gliflozins. The present study found that phloridzin highly accumulated in Malus rockii Rehder. The content of phloridzin in M. rockii was the highest among wild plants, with the percentage of 15.54% in the dry leaves. The structure of phloridzin was revised by proton exchange experiments and extensive 2D NMR spectra. Phloridzin exhibited significant hypolipidemic activity in golden Syrian hamsters maybe by increasing the expression of CYP7A1, at the doses of 50 mg/kg and 200 mg/kg. The total performance of anti-hyperlipidemic effect of phloridzin may be superior to that of lovastatin, though lovastatin was more active than phloridzin. In addition, phloridzin exhibited moderate antimalarial activity with inhibition ratio of 31.3 ± 10.9% at a dose of 25 mg/kg/day, and showed moderate analgesic activity with 28.0% inhibition at a dose of 50 mg/kg.

Antimalarial Natural Products

Natural products have made a crucial and unique contribution to human health, and this is especially true in the case of malaria, where the natural products quinine and artemisinin and their derivatives and analogues, have saved millions of lives. The need for new drugs to treat malaria is still urgent, since the most dangerous malaria parasite, Plasmodium falciparum, has become resistant to quinine and most of its derivatives and is becoming resistant to artemisinin and its derivatives. This volume begins with a short history of malaria and follows this with a summary of its biology. It then traces the fascinating history of the discovery of quinine for malaria treatment and then describes quinine's biosynthesis, its mechanism of action, and its clinical use, concluding with a discussion of synthetic antimalarial agents based on quinine's structure. The volume then covers the discovery of artemisinin and its development as the source of the most effective current antimalarial drug, including summaries of its synthesis and biosynthesis, its mechanism of action, and its clinical use and resistance. A short discussion of other clinically used antimalarial natural products leads to a detailed treatment of other natural products with significant antiplasmodial activity, classified by compound type. Although the search for new antimalarial natural products from Nature's combinatorial library is challenging, it is very likely to yield new antimalarial drugs. The chapter thus ends by identifying over ten natural products with development potential as clinical antimalarial agents.

Sesquiterpenoids and their glycosides from Dobinea delavayi (Baill.) Baill

Eight undescribed sesquiterpenoids, including two eudesmane glycosides dobinosides A and B, five eudesmane aglycones dobinins Q-U, and one germacrane dobinin P, were isolated from the 80% ethanol extract of roots of Dobinea delavayi. Their structures were elucidated by extensive spectroscopic data (1D and 2D NMR, HR-ESI-MS) and single-crystal X-ray diffraction analysis. Dobinoside A, dobinins Q and R, as well as six reported eudesmane sesquiterpenoids, were evaluated for their in vivo antimalarial activities against Plasmodium yoelii BY265RFP in mice. A summary of preliminary structure-activity relationship of eudesmane sesquiterpenoids for in vivo antimalarial activity was described.

Further terpenoids from the Chloranthaceae plant Chloranthus multistachys and their anti-neuroinflammatory activities

Three labdane-type [multisins A-C (1-3)], two guaiane-type [multisins D (4) and E (5)], and one eudesmane-type [multisin F (6)] previously undescribed terpenoids, together with 14 mono- (7-20) and seven dimeric- (21-27) known terpenoids, were isolated from the 90% MeOH extract of the whole plant of Chloranthus multistachys. Their structures and absolute configurations were determined by extensive spectroscopic methods and electronic circular dichroism (ECD) calculations. Compounds 4 and 5 are rare trinor-sesquiterpenes with a de-isopropyl guaiane skeleton, whereas compound 6 is a rearranged dinor-eudesmene featuring an uncommon octahydro-1H-indene ring system. Among the isolates, the dimeric lindenane sesquiterpenoid shizukaol C (25) exhibited the most potent (IC₅₀ = 8.04 μM) anti-neuroinflammatory activity by inhibiting the nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated murine BV-2 microglial cells.