Protective effects of 5,7,4'-trihydroxy-6,3'dimethoxy-flavone 5-O-α-l-rhamnopyranoside, isolated from Annona squamosa leaves in thyrotoxicosis and in hepatic lipid peroxidation in rats

Phytochemical constituents, bioactivities, and applications of custard apple (Annona squamosa L.): A narrative review

Annona squamosa L. (Annonaceae) is a versatile tree with an edible fruit showing abundant medicinal and industrial applications. The nutritional values of this plant are due to carbohydrates, proteins, amino acids, and vitamins. Ethnopharmacological uses referred to treatment of dysentery, headlice, cancer sores, purgative, and tonic effects. The main reported biological activities for A. squamosa L. were cytotoxic, antidiabetic, antimicrobial, antiparasitic, antioxidant, antimalarial, molluscidal, anthelmintic and insecticidal activities, and its chemical classes encompassed alkaloids, diterpenes, acetogenins, and cyclopeptides. The nutritional content of A. squamosa L. and their main chemical components, biological effects, and the different applications were discussed in this review. This comprehensive review strived to compile all the relevant data in the period between 1990 and 2023 covering databases PubMed, ScienceDirect, Web of Science, Googlescholar and Reaxys concerning A. squamosa L. different parts with their reported phytochemical constituents and biological activities to integrate a better understanding of the medicinal values.

Custard Apple (Annona squamosa L.) Leaves: Nutritional Composition, Phytochemical Profile, and Health-Promoting Biological Activities

Annona squamosa L. (custard apple) belongs to the family Annonaceae and is an important tropical fruit cultivated in the West Indies, South and Central America, Ecuador, Peru, Brazil, India, Mexico, the Bahamas, Bermuda, and Egypt. Leaves of custard apple plants have been studied for their health benefits, which are attributed to a considerable diversity of phytochemicals. These compounds include phenol-based compounds, e.g., proanthocyanidins, comprising 18 different phenolic compounds, mainly alkaloids and flavonoids. Extracts from Annona squamosa leaves (ASLs) have been studied for their biological activities, including anticancer, antidiabetic, antioxidant, antimicrobial, antiobesity, lipid-lowering, and hepatoprotective functions. In the current article, we discussed the nutritional and phytochemical diversity of ASLs. Additionally, ASL extracts were discussed with respect to their biological activities, which were established by in vivo and in vitro experiments. A survey of the literature based on the phytochemical profile and health-promoting effects of ASLs showed that they can be used as potential ingredients for the development of pharmaceutical drugs and functional foods. Although there are sufficient findings available from in vitro and in vivo investigations, clinical trials are still needed to determine the exact effects of ASL extracts on human health.

Agnucastoside C, isolated from Moringa oleifera ameliorates thyrotoxicosis and liver abnormalities in female mice

Background

In the present investigation an attempt was made to evaluate the potential of agnucastoside C (ACC), isolated from the leaves of Moringa oleifera in ameliorating thyrotoxicosis, hepatic lipid peroxidation (LPO) and hyperglycemia in female mice.

Methods

L-thyroxine (L-T4) at 0.5 mg/kg/d was administered through intra-peritoneal route for 15 consecutive days to induce thyrotoxicosis and then the effects of three different doses (10, 20 and 30 mg/kg body weight) of the isolated ACC for 21 days were investigated on the changes in serum thyroid hormones, insulin, glucose, different lipids; hepatic lipid peroxidation, enzymatic antioxidants such as superoxide dismutase, catalase and glutathione peroxidase, advanced oxidation protein products, reduced glutathione and in lipid peroxides.

Results

Following the administration of L-T4, serum T3, T4, insulin, glucose levels and the tissue LPO were increased with a decrease in serum thyroid stimulating hormone and antioxidative enzymes. However, administration of the test compound to hyperthyroid animals significantly decreased the levels of thyroid hormones, glucose and lipid peroxidation and normalized the concentration of insulin and tissue antioxidants, suggesting its antithyroid, antihyperglycemic and antiperoxidative potential. The T4-induced adverse effects on liver histology were also abolished. These findings suggest the possible use of the test compound in ameliorating thyrotoxicosis.

Conclusion

ACC exhibited antithyroidic, antihypoglycemic, antioxidative and insulin normalizing activities.

Flavonoid epimers from custard apple leaves, a rapid screening and separation by HSCCC and their antioxidant and hypoglycaemic activities evaluation

Leaves of custard apple are widely used in many places as a popular dietary supplement for the treatment of diabetes. Flavonoids are known to have anti-diabetic activity. In this study, the main flavonoid epimers were separated. The crude extract was first screened by HPLC-DAD before and after incubation with DPPH method to evaluate the antioxidants. An efficient extraction method was employed to remove non-flavonoid components. Subsequently, five main flavonoids with two pairs of epimers including quercetin-3-O-robinobioside, rutin, quercetin-3-O-β-D-glucoside, kaempferol-3-O-robinobioside, and kaempferol-3-O-rutinoside were successfully separated by high-speed counter-current chromatography with ethyl acetate/n-butanol/water (4:1:5, v/v) coupled with online-storage inner-recycling mode. The structures of the separated compounds were identified by spectral techniques. The purity of the separated flavonoid glycosides was over 98%, as determined by HPLC. The separated pure constituents were found to possess the antioxidant capacities following DPPH radical scavenging protocol. The compounds (1-3) exhibited better antioxidant activity. Furthermore, the glucose uptake of crude flavonoid extract had better results than the crude ethanol extract. The present study demonstrates that the efficacy of custard apple leaves in lowering glucose level, and antioxidant capacities of separated pure compounds probably appear to be predominantly responsible for hypoglycaemic properties on HepG2 cells.

Allylpyrocatechol, isolated from betel leaf ameliorates thyrotoxicosis in rats by altering thyroid peroxidase and thyrotropin receptors

Allylpyrocatechol (APC) was isolated from betel leaf and its possible role in L-thyroxin (L-T4)-induced thyrotoxic rats was evaluated. The disease condition, thyrotoxicosis was confirmed by higher levels of thyroid hormones and low thyrotropin (TSH) in serum. Increased hepatic activities of 5'-mono-deiodinase(5'D1), glucose-6-phospatase (G-6-Pase); serum concentrations of alanine transaminase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase(LDH) and tumour necrosis factor-alpha(TNF-α) were observed in thyrotoxic rats. Hepatic lipid peroxidation(LPO) was also increased and the endogenous antioxidants were depleted in these rats. In western blot analysis thyroid peroxidase expression was found to be reduced, whereas thyrotropin receptor(TSHR) expression was enhanced in thyroid gland of these animals. On the other hand, APC treatment in thyrotoxic rats decreased the levels of serum thyroid hormones, ALT, AST, TNF-α and LDH, as well as hepatic 5' D1 and G-6-Pase activities. However, it increased the serum TSH levels. APC also reduced the hepatic LPO and increased the cellular antioxidants in thyrotoxic rats. However, expression of TSHR was inhibited and TPO was increased by APC. The test compound also improved histological features in both liver and thyroid. Present report appears to be the first one that indicates the positive role of APC in ameliorating T4-induced thyrotoxicosis.

Chavibetol corrects thyrotoxicosis through alterations in thyroid peroxidase

Thyrotoxicosis is a clinical syndrome that commonly results from excess secretion and/or release of thyroid hormones in the circulation. It affects most of the body systems and if not treated properly may lead to serious health problems. In this investigation, we isolated a phenolic compound, chavibetol (CHV) from Piper betel leaf and evaluated its possible ameliorative effects in thyrotoxicosis of rats. Adult female rats were rendered thyrotoxic by the administration of L-thyroxine (L-T₄) at 500 μg/kg/day, i.p., for 12 days, and then chavibetol (20.0 mg/kg, p.o.) was administered for 2 weeks. L-T₄ administration elevated the concentration of serum thyroxine and triiodothyronine, activities of alanineaminotransferase and aspartate aminotransferase, and decreased the thyrotropin level as well as the expression of thyroid peroxidase (TPO). Further, it increased the activities of hepatic 5'mono-deiodinase-I, glucose-6--phosphatase, sodium-potasium-ATPase, and lipid peroxidation, and depleted the cellular antioxidants. However, chavibetol treatment to thyrotoxic rats normalized almost all these indices including TPO and also preserved the integrity of thyroid tissues suggesting its potential to correct thyrotoxicosis. Effects of CHV were more or less similar to a conventional antithyroid drug, propylthiouracil (PTU).

A Review on Annona squamosa L.: Phytochemicals and Biological Activities

Annona squamosa L. (Annonaceae) is a fruit tree with a long history of traditional uses. A. squamosa is an evergreen plant mainly located in tropical and subtropical regions. Srikayas, the fruits of A. squamosa, are extensively used to prepare candies, ice creams and beverages. A wide range of ethno-medicinal uses has been related to different portions of A. squamosa, such as tonic, apophlegmatisant, cool medicine, abortient and heart sedative. Numerous research projects on A. squamosa have found that it has anticancer, anti-oxidant, antidiabetic, antihypertensive, hepatoprotective, antiparasitic, antimalarial, insecticidal, microbicidel and molluscicidal activities. Phytochemistry investigations on A. squamosa have considered annonaceous acetogenins (ACGs), diterpenes (DITs), alkaloids (ALKs) and cyclopeptides (CPs) as the main constituents. Until 2016, 33 DITs, 19 ALKs, 88 ACGs and 13 CPs from this species were reported. On the basis of the multiple researches on A. squamosa, this review strives to integrate available information on its phytochemicals, folklore uses and bioactivities, hoping to promote a better understanding of its medicinal values.