Glycosides of naphthohydroquinones and anthraquinones isolated from the aerial parts of Morinda parvifolia Bartl. ex DC (Rubiaceae) increase p53 mRNA expression in A2780 cells

Plant anthraquinones: Classification, distribution, biosynthesis, and regulation

Anthraquinones are polycyclic compounds with an unsaturated diketone structure (quinoid moiety). As important secondary metabolites of plants, anthraquinones play an important role in the response of many biological processes and environmental factors. Anthraquinones are common in the human diet and have a variety of biological activities including anticancer, antibacterial, and antioxidant activities that reduce disease risk. The biological activity of anthraquinones depends on the substitution pattern of their hydroxyl groups on the anthraquinone ring structure. However, there is still a lack of systematic summary on the distribution, classification, and biosynthesis of plant anthraquinones. Therefore, this paper systematically reviews the research progress of the distribution, classification, biosynthesis, and regulation of plant anthraquinones. Additionally, we discuss future opportunities in anthraquinone research, including biotechnology, therapeutic products, and dietary anthraquinones.

The isolation of water-soluble natural products - challenges, strategies and perspectives

Covering period: up to 2019Water-soluble natural products constitute a relevant group of secondary metabolites notably known for presenting potent biological activities. Examples are aminoglycosides, β-lactam antibiotics, saponins of both terrestrial and marine origin, and marine toxins. Although extensively investigated in the past, particularly during the golden age of antibiotics, hydrophilic fractions have been less scrutinized during the last few decades. This review addresses the possible reasons on why water-soluble metabolites are now under investigated and describes approaches and strategies for the isolation of these natural compounds. It presents examples of several classes of hydrosoluble natural products and how they have been isolated. Novel stationary phases and chromatography techniques are also reviewed, providing a perspective towards a renaissance in the investigation of water-soluble natural products.

Iridoids with anti-inflammatory effect from the aerial parts of Morinda officinalis How

Morinda officinalis How was widely applied to alleviate symptom like impotence, menstrual disorders, osteoporosis, and rheumatoid arthritis. To expand resources usage, phytochemistry of the aerial parts was studied and the structures of compounds were elucidated based on NMR, HRESIMS, IR and UV. Moreover, the anti-inflammatory effect and possible mechanism were investigated by Griess kit, RT-qPCR, ELISA, western blot and molecular docking on LPS-induced inflammation in RAW 264.7 cells. Herein, we isolated and identified 16 iridoid derivatives, including seven new iridoids officinaloside A-G (1-7) and nine known iridoids. All the compounds were safe to RAW 264.7 cells. Luckily, compounds 5 and 6 showed inhibitory effect on production of NO, and decreased the expression of inflammatory cytokines at mRNA and protein levels in a dose-dependent way. The possible mechanism of their anti-inflammation may be the affinity interaction between 5 with COX-2 protein, and 6 with iNOS protein. Overall, compounds 5 and 6 exert promising effects in inhibiting inflammatory cytokines, indicating that they could be used as lead compounds for developing health products or clinical practice for inflammation, which provides a scientific basis for further sustainable development and usage of the aerial parts of Morinda officinalis How.

Water-soluble alkaloids isolated from Portulaca oleracea L

Fifteen new water-soluble alkaloids were obtained from the fresh herbs of Portulaca oleracea L. The structures of 15 alkaloids 1-15 were established according to spectroscopic data, and the stereoconfigurations were determined based on experimental and calculated electronic circular dichroism (ECD) data and single crystal X-ray diffraction. Alkaloids 1-15 were found to display good anti-inflammatory activity at 10 μM and could significantly reduce the interleukin-6 (IL-6) and nitric oxide (NO) levels induced by lipopolysaccharide (LPS) in RAW 264.7 macrophages.

Indian Morinda species: A review

Morinda is a largest genus of Rubiaceae family, and its 11 species are found in India. In India, plant species are known by several common names as great morinda, Indian mulberry, noni, beach mulberry and cheese fruit. Various Morinda products (capsules, tablets, skin products and fruit juices) are available in the market, used by people for treatment of several health complaints. A diversity of phytochemicals including iridoids, flavonoids, flavonoid glycosides, anthraquinones, coumarins, lignanas, noniosides, phenolics and triterpenoids have been reported from Morinda species. Morinda species are used in the treatment of inflammation, cancer, diabetes, psyquiatric disorders, and bacterial and viral infections. The noni fruit juice (Morinda citrifolia) and its products are used clinically in the treatment of cancer, hypertension and cervical spondylosis affecting patients. M. citrifolia fuit juice, with different doses, is used in the maintaining blood pressure and reducing of superoxides, HDL and LDL levels. Similarly, oligosaccharide capsules and tablets of root extract of M. officinalis are recommended as medicine for the treatment of kidney problems and sexual dysfunctions of patients. The toxicological studies revealed that higher doses of fruit juice (4,000 or 5,000 mg/kg) of M. citrifolia for 2 or more months cause toxic effects on liver and kidneys. M. officinalis root extracts (ethanolic and aqueous) are found fully safe during treatment of diseases. A large number of reviews are available on M. citrifolia but very few studies are conducted on other Indian Morinda species. This review reports the comprehensive knowledge on state-wise distribution, botany, ethnomedicinal uses, phytochemistry, pharmacological activities, clinical applications and toxicological evaluations of 11 species of Morinda found in India.

Recent advances in allelopathy for weed control: from knowledge to applications

Allelopathy is the biological phenomenon of chemical interactions between living organisms in the ecosystem, and must be taken into account in addressing pest and weed problems in future sustainable agriculture. Allelopathy is a multidisciplinary science, but in some cases, aspects of its chemistry are overlooked, despite the need for a deep knowledge of the chemical structural characteristics of allelochemicals to facilitate the design of new herbicides. This review is focused on the most important advances in allelopathy, paying particular attention to the design and development of phenolic compounds, terpenoids and alkaloids as herbicides. The isolation of allelochemicals is mainly addressed, but other aspects such as the analysis and activities of derivatives or analogs are also covered. Furthermore, the use of allelopathy in the fight against parasitic plants is included. The past 12 years have been a prolific period for publications on allelopathy. This critical review discusses future research areas in this field and the state of the art is analyzed from the chemist's perspective. © 2019 Society of Chemical Industry.

Anti-inflammatory terpenes from Schefflera rubriflora C. J. Tseng & G. Hoo with their TNF-α and IL-6 inhibitory activities

The 95% ethanol extract and its EtOAc and n-BuOH fractions obtained from the leaves and twigs of Schefflera rubriflora C. J. Tseng & G. Hoo showed significant inhibitory activities (33.6%, 35.7% and 40.6%, respectively) against croton oil-induced ear inflammation in mice. Bioactivity-guided isolation and separation gave eight previously undescribed terpenes or terpene glycosides. Structural elucidation was based on UV, IR, and NMR spectroscopy, MS, experimental and calculated ECD data, and Mosher's method. To identify anti-inflammatory components from the extract, all the compounds were evaluated for tumor necrosis factor-α (TNF-α) and interleukine-6 (IL-6) inhibitory activities. Four undescribed compounds inhibited mRNA expression of TNF-α and IL-6 with IC₅₀ values of 15.3-52.4 μM.