Diterpenoids as potential anti-malarial compounds from Andrographis paniculata

Red-Fleshed Apple Flavonoids Extract Alleviates Male Reproductive Injury Caused by Busulfan in Mice

In this research, we analyzed the protective effects of red-fleshed apple flavonoid extracts (RAFEs) on male reproductive injury induced by busulfan, using both in vitro and in vivo models. In the cell-based experiments, RAFEs significantly improved cell viability and proliferation rates compared to control groups. Similarly, in vivo testing with male mice showed that RAFEs and whole apple flavonoid extracts (WAFEs) enhanced various biochemical and liver function-related indicators in the testes; however, RAFEs demonstrated superior efficacy in mitigating testicular damage. Through immunohistochemistry, qRT-PCR, and Western blotting, we found that RAFEs notably enhanced the expression of spermatogenesis-related genes. Moreover, RAFEs increased the expression of oxidative stress- and apoptosis-related genes, thereby effectively reducing oxidative damage in the testes. These findings highlight the potential of RAFEs as natural agents for the prevention and treatment of male reproductive injury, paving the way for future research and potential therapeutic applications.

Plant Extracts as a Source of Natural Products with Potential Antimalarial Effects: An Update from 2018 to 2022

Malaria kills more than 500,000 people yearly, mainly affecting Africa and Southeast Asia. The disease is caused by the protozoan parasite from the genus Plasmodium, with Plasmodium vivax and Plasmodium falciparum being the main species that cause the disease in humans. Although substantial progress has been observed in malaria research in the last years, the threat of the spread of Plasmodium parasites persists. Artemisinin-resistant strains of this parasite have been reported mainly in Southeast Asia, highlighting the urgent need to develop more effective and safe antimalarial drugs. In this context, natural sources, mainly from flora, remain underexplored antimalarial spaces. The present mini-review explores this space focusing on plant extracts and some of their isolated natural products with at least in vitro antiplasmodial effects reported in the literature comprising the last five years (2018-2022).

A New Source of Diterpene Lactones From Andrographis paniculata (Burm. f.) Nees—Two Endophytic Fungi of Colletotrichum sp. With Antibacterial and Antioxidant Activities

Endophytic fungi of medicinal plants are abundant, and their metabolites often have antioxidant, antibacterial, and antitumor effects and can produce secondary metabolites identical or similar to those of their hosts, which can mitigate the problem of insufficient supply of medicinal plants. In this study, we screened endophytic fungi for strains that produce the same diterpene lactones as Andrographis paniculata based on their biological activity. Firstly, the dominant group of endophytic fungi of Andrographis paniculata was screened and pathogenicity was studied using Koch’s rule. Secondly, DPPH, ABTS, OH, PTIO radical scavenging, and FRAP assays were used to detect the antioxidant activity of the extracellular extracts of the strains, and total phenol and total flavonoid contents of the strains with high antioxidant capacity were determined. S. aureus, B. subtilis, E. coli, and P. aeruginosa were used to determine the antibacterial activity of the mycelial extracts of the strains. Finally, the secondary metabolites of the mycelial extracts of the strains were examined by high-performance liquid chromatography. The results showed that 32 strains of Andrographis paniculata were relatively isolated > 70% and non-pathogenic. Extracellular extracts of strains AP-1 and AP-4 showed vigorous antioxidant activity, and AP-4, AP-12, AP-47, and AP-48 showed antibacterial activity against four strains of bacteria. The HPLC results indicated that the mycelial extracts of AP-4 and AP-12 contained diterpene lactones. The two endophytic fungi were recognized as Colletotrichum sp. The study successfully obtained diterpene lactones from the endophytic fungus of Andrographis paniculata and confirmed the feasibility of using endophytic fungal strains to produce active substances consistent with the host. It was also useful for exploring endophytic fungi and medicinal plants. The relationship provides theoretical guidance.

Biotechnological production of diterpenoid lactones from cell and organ cultures of Andrographis paniculata

Andrographis paniculata (AP) is a medicinal plant that is traditionally used in Indian, Chinese, Malay, Thai, and Oriental system of medicines to treat various disorders. AP consists of andrographolide (AD), 14-deoxy-11,12-didehydroandrographolide (DDAD), and neoandrographolide (NAD) as major diterpene lactones which has extremely bitter properties; therefore, AP is commonly called "King of bitters." AD, DDAD, and NAD are reported to possess therapeutic values such as antioxidant, immunostimulatory, hepatoprotective, anti-cancer, anti-inflammatory, anti-rheumatoidal, anti-malarial, anti-leishmanial, anti-fertility, anti-obesity, antipyretic, and antimicrobial attributes. According to the Indian Pharmacopoeia, the leaves and tender shoots of AP yield up to 1%, 0.16%, and 0.11% of AD, DDAD, and NAD, respectively, on a dry-weight basis. However, variability in the accumulation of AD, DDAD, and NAD in plants has been reported with respect to species, genotype, season, phenological stage, plant part used, and geography of a region of cultivation. Therefore, cell and tissue culture systems especially cell, shoot, and adventitious root cultures are explored as alternatives for constant and higher production of AD, DDAD, and NAD. This review explores the prospects of exploiting the plant cell and tissue culture systems for the controlled production of AD, DDAD, and NAD. Various strategies such as elicitation by using biological and chemical elicitors are explored for the enhancement of accumulation of AD, DDAD, and NAD in cell and organ cultures. KEY POINTS: • This review explores the possibilities of diterpene lactone production from cell and organ cultures. • Various strategies are explored for the enhanced accumulation of AD, DDAD, and NAD in cell and organ cultures. • Prospects of diterpene lactone production are highlighted.

Secondary metabolite profiling and characterization of diterpenes and flavones from the methanolic extract of Andrographis paniculata using HPLC-LC-MS/MS

Background

Andrographis paniculata is a well-known medicinal plant that contains various classes of bioactive secondary metabolites. It is widely used by the traditional medicinal healers for treatment of malaria and other diseases. There is an urgent need for screening of potent novel compounds from the methanol extract of A. paniculata. Earlier, we obtained appreciable in vitro anti-malarial activity (IC50-10.75 μg/ml) in the same plant. In current study, we developed novel analytical methods for rapid identification and characterization of diterpenes and flavones using chromatographic and spectroscopic techniques and identified major compounds that might possess anti-malarial activities.

Results

Based on the chromatographic and mass spectrometric features, we have identified a total of 74 compounds (25 compounds from positive ion mode; 49 compounds from negative ion mode). The mass spectrum data predicted andrographolide (15%) presence in the highest amount in both positive and negative ion modes. Based on the percentage purity, Andrographolide and skullcapflavone I was selected as representative class of diterpenes and flavones for fragmentation studies.

Conclusions

The result led to identification of Neoandrographolide, andrographolactone, 14-dehydroxy-11,12-didehydroandrographolide, skullcapflavone I, and 5-Hydroxy-2′,7,8-tri methoxy flavone from the methanolic extract of A. paniculata that is used in traditional medicine by tribal healers of Amarkantak region for treating malaria. These could be lead compounds for the development of novel anti-malarial drugs.