A comprehensive review on polysaccharides with hypolipidemic activity: Occurrence, chemistry and molecular mechanism

Currently, research on natural products is facing challenging future in various aspects. A large group of natural polysaccharides such as β-glucan, cellulose, hemicellulose, chitin, pectin, agaropectin, heteroglycans, lignins, hydrocolloids, homopolysaccharides, heteropolysaccharides were studied extensively for their various therapeutical potential. Several research works have already demonstrated those polysaccharides has tremendous health benefits, and found to exhibit anticancer, antiviral, immunomodulatory, antimicrobial, anticoagulant, anti-inflammatory, antidiabetic, antioxidant and antitumor activities. Different mushroom, plant, fungus, algae, vegetables, microalgae etc. are some important source of several polysaccharide macromolecules such as glucans, ulvan A, ulvan B, fucoidan, rhamnan sulfate, laminarin sulfate, agar, alginate, heteroglycans. Earlier research work demonstrated that natural polysaccharides have the highest ability to carry biological properties along with some biopolymers like as proteins and nucleic acids due to their structural variability. The preventive effect of these biomacromolecules was extensively studied, especially their beneficial effect on chronic metabolic conditions like dyslipidemia and related disorders. Dyslipidemia is a serious metabolic disorder associated with coronary heart disease, coronary artery diseases, hypercholesterolemia, atherosclerosis, etc. Dietary natural polysaccharides could play an important role in the management and prevention of dyslipidemia. Polysaccharides from natural sources mainly sulfated polysaccharides exhibited predominant lipid-lowering and cholesterol-lowering activities through different mechanisms. Polysaccharides isolated from different edible plants, vegetables, plant, algae, mushroom with higher biological activities, particularly hypolipidemic activity were highlighted in this paper, in a way for their futuristic therapeutic application. This review aims to comprehensively discuss overall advances in hypolipidemic activity of polysaccharides, including their sources, structural characteristic and chemistry, biological activity and their probable mode of action.

Diabetes mellitus and COVID-19: Understanding the association in light of current evidence

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have posed a problematic healthcare situation worldwide since December 2019. Diabetes mellitus is associated with an increased risk and severity of coronavirus disease 2019 (COVID-19). While interacting with various other risk factors, high blood sugar was found to reduce immunity and increase the replication of SARS-CoV-2. Oxidative stress and the release of pro-inflammatory cytokines are greater in diabetic individuals than in healthy people, worsening the outcome of SARS-CoV-2 infection in diabetics. Increased expression of furin and angiotensin converting enzyme 2 (ACE-2) receptor in the hyperglycemic environment may promote the entry of SARS-CoV-2 in the host cell. COVID-19 infection primarily modulates immune and inflammatory responses, and may cause a cytokine storm, resulting in possible lethal outcomes in diabetics. An experimental report suggests that ACE expressed in the pancreas and the SARS-CoV-2 virus invariably destroy β-cells which contain ACE-2 receptors and results in acute diabetes. Moreover, COVID-19 also causes hyperglycemia in an individual with diabetes which may be related to insulin resistance and destruction of β-cells during SARS-CoV-2 infection. Early observations also suggest a correlation between oral hypoglycemic agents and the risk of COVID-19. This review focused on the possible cause and mechanism involved in SARS-CoV-2 infection in diabetics and the role of antidiabetic drugs in COVID-19.

An Ethnomedicinal Survey of Antidiabetic Plants and Preliminary Evaluation of Antioxidant, Hypoglycemic Activity Maesa indica Leaves, a Folk Antidiabetic Plant of Manipur, India

Background:

Manipur is a small state of India, well known for its folk medicine. Folk medicine practitioners of the state use a number of plants to manage diabetes mellitus.

Objective:

This is an ethnomedicinal survey to find folk antidiabetic plants of the Thoubal district of Manipur, India. This study aimed to investigate the antioxidant and hypoglycemic potential of the chosen medicinal plant.

Methods:

An ethnomedicinal survey was carried out in Thoubal district, Manipur to find out antidiabetic plants regularly used by tribal/folk medicinal practitioners. Based on the information, Maesa indica leaves extracts (ethanol extract, MIE; ethyl acetate extract, MIEA; petroleum ether extract, MIPE) were further investigated for in vitro antioxidant and antidiabetic activity. Acute hypoglycemic activity (streptozotocin-induced diabetes model) was evaluated and NGOGTT tests were conducted to evaluate the hypoglycemic activity of Maesa indica leaves.

Results:

Ethnomedicinal survey revealed that folk medicinal practitioners regularly used 15 antidiabetic plants. Maesa indica is a plant of choice of folk medicinal practitioners. MIE was found to possess strong oxidative haemolysis inhibition, nitric oxide radical and DPPH radical scavenging effect with IC50 values of 54.5, 34.1 and 19.2 μg/mL, respectively. MIE inhibited α-glucosidase and α-amylase with IC50 values of 18.2 and 31.2 μg/mL, respectively. MIE and MIEA produced considerable hypoglycemic activity when tested through the NG-OGTT model. MIE (500 mg/kg, b.w.) asserted significant acute hypoglycemic activity by reducing blood glucose level after 1h, 2h, 3h, 5h, and 12h of drug administration in streptozotocin-induced diabetic rats.

Conclusion:

The present study showed that the ethanol extract of Maesa indica leaves possesses better activity compared to ethyl acetate and petroleum ether extract. This study also confirmed the ethnobotanical claim about traditional use of plant and antidiabetic potential of M. indica leaves.

Natural Starch in Biomedical and Food Industry: Perception and Overview

Utilization of native starch is increasing globally because of its wide distribution and natural occurrence. Starch is mainly abundant in tubers and food grains. Scientific research on starch is increasing in recent years due to its unique physiochemical and biomedical properties. Native starch is an emerging biopolymer and copolymer in the biomedical and pharmaceutical areas due to its renewability, biocompatibility, biodegradability, and relative inexpensiveness. Today, there is an increasing interest in natural starches to design and produce diverse products due to their pertinent structural properties and non-toxicity. Due to these attributes, these natural polymers are becoming functional core materials in the biomedical industry, construction materials, medicine industry, food industry, food packaging, and carrier for active drugs. In this paper, we mainly attempt to analyze the physicochemical attributions and the biomedical applications on native or non-conventional starches obtained from the natural botanical sources.

Revival, modernization and integration of Indian traditional herbal medicine in clinical practice: Importance, challenges and future

In spite of incredible advances in modern science, technology and allopathic medicine a large we are unable to provide quality healthcare to all. Traditional medicine particularly herbal medicine considered as a major healthcare provider around the globe particularly in rural and remote areas. A large section of people depends on such medicine for their primary healthcare mainly in underdeveloped or developing countries. Indian traditional medicinal system like Ayurveda, Siddha and Unani has a very rich history of their effectiveness; modern research also acknowledged the importance of such medicine. Indian traditional medicine or medicinal plants are also considered as a vital source of new drug. Mainstreaming of such medicine is important for the people. Several steps have been taken in India to promote such medicine and to integrate them into clinical practice. Evidence based incorporation of Indian traditional medicine in clinical practice will help to provide quality healthcare to all.

Total phenolic, total flavonoid content, and antioxidant capacity of the leaves of Meyna spinosa Roxb., an Indian medicinal plant

AIM

The objective of the present study was to determine the total phenolic and total flavonoid contents, and to evaluate the antioxidant potential of different leaf extracts of Meyna spinosa Roxb. ex Link, a traditional medicinal plant of India.

METHODS

Free radical scavenging and antioxidant potential of the methanol, ethyl acetate, and petroleum ether extracts of Meyna spinosa leaves were investigated using several in vitro and ex vivo assays, including the 2, 2-diphenyl-picrylhydrazyl radical scavenging, superoxide anion scavenging, hydroxyl radical scavenging, nitric oxide radical scavenging, hydrogen peroxide scavenging activity, metal chelating assay, and reducing power ability method. Total antioxidant activity of the extracts was estimated by the ferric thiocyanate method. Inhibition assay of lipid peroxidation and oxidative hemolysis were also performed to confirm the protective effect of the extracts. Total phenolic and total flavonoid contents of the extracts were estimated using standard chemical assay procedures.

RESULTS

Methanol extracts showed the highest polyphenolic content and possessed the better antioxidant activity than the other two extracts. Total phenolic and total flavonoid contents in the methanol extract were (90.08 ± 0.44) mg gallic acid equivalents/g and (58.50 ± 0.09) mg quercetin equivalents/g, respectively. The IC50 of the methanol extract in the DPPH(·), superoxide anion, hydroxyl radical, nitric oxide radical, hydrogen peroxide scavenging activity and metal chelating assays were (16.4 ± 0.41), (35.9 ± 0.19), (24.1 ± 0.33), (23.7 ± 0.09), (126.8 ± 2.92), and (117.2 ± 1.01) μg·mL(-1), respectively. The methanol extract showed potent reducing power ability, total antioxidant activity, and significantly inhibit lipid peroxidation and oxidative hemolysis which was similar to that of standards.

CONCLUSION

The results indicated a direct correlation between the antioxidant activity and the polyphenolic content of the extracts, which may the foremost contributors to the antioxidant activity of the plant. The present study confirmed that the methanol extract of Meyna spinosa leaves is a potential source of natural antioxidants.

Cisplatin-induced nephrotoxicity in mice: protective role of Leea asiatica leaves

Cisplatin is a popular anticancer drug, but its side effects like nephrotoxicity and hepatotoxicity due to oxidative stress limited its clinical use. In tis study, nephoprotective effect of fractions of Leea asiatica (Leeaceae) leaves was assessed against cisplatin induced toxicity in rats. Leaves of L. asiatica extracted with methanol, ethyl acetate, petroleum ether, and evaluated for in vitro and ex vivo antioxidant activity using several assay models. Methanol extract showed better antioxidant effects, and contain higher amount of phenolic (77.75 ± 0.87 mg GAE/g of dry material) and flavonoid compound (60.98 ± 0.58 mg QE/g of dry material) compared with other extracts. Hance methanol extract was selected for further investigation and fractionated with methanol, ethyl acetate, petroleum ether. Protective effect of methanol extract and its fractions was evaluated against cisplatin (20 mg/kg, i.p.) induced nephrotoxicity. Pretreatment with methanol extract (150 and 300 mg/kg), and its fractions especially methanol, ethyl acetate fraction (75 and 150 mg/kg) significantly reduced blood urea nitrogen, serum creatinine, uric acid levels, and decreased malondialdehyde level and increase total protein and albumin level (p < 0.05, 0.01). Ethyl acetate fraction produced highest nephroprotective, possibly by inhibiting lipid peroxidation process. Result suggested that ethyl acetate fraction possesses potent nephroprotective activity and can be used an adjunct therapy aiming to improve the effectiveness of several nephrotoxic drugs.

Antitussive, expectorant activity of Marsilea minuta L., an Indian vegetable

Marsilea minuta L., an aquatic or sub-aquatic fern used as a vegetable, has wide applications in traditional/folk medicine in India and Bangladesh. In our study, we evaluated the antitussive, expectorant activity of M. minuta crude extracts. The antitussive activity of M. minuta methanol, ethyl acetate, and petroleum ether extracts was evaluated using ammonia and sulfur dioxide induced mice coughing. The expectorant activity was evaluated by the volume of phenol red in mice's tracheas. Extracts significantly increased mice's cough latent period and inhibited the frequency of cough induced by ammonia and sulfur dioxide, and improved tracheal phenol red output in expectorant evaluation. Methanol extract produced the highest activity in all tested models. Methanol extract at 500 mg/kg showed 59.5% and 55.8% inhibition in the number of coughing induced by ammonium liquor and SO₂, respectively, while it showed 89.3% increase in phenol red secretion at the same dose, which showed superior activity compared to other extracts. The present study provided evidence for M. minuta to be used as an antitussive and expectorant in Indian folk medicine.

Anti-inflammatory, analgesic, and antioxidant activities of Pisonia aculeata: folk medicinal use to scientific approach

CONTEXT

Pisonia aculeata leaves (Nyctagenaceae), a Folk medicinal plant used in the treatment of several inflammation, pain, and oxidative stress associated diseases.

OBJECTIVE

To evaluate anti-inflammatory, analgesic, and antioxidant potential of crude methanol extract of P. aculeata leaves (MEPA).

MATERIALS AND METHODS

Analgesic and anti-inflammatory activities of MEPA (250 and 500 mg/kg) were evaluated using writhing, formalin, hot plate, tail flick, carrageenan-induced paw edema test, and membrane stabilizing activity. Free radical scavenging activity, total phenolic and flavonoid contents of MEPA were also determined using standard methods.

RESULTS

Oral administration of MEPA showed significant (p < 0.001) inhibition of paw edema, pronounced at 4 h and 5 h after carrageenan injection, and at 200 µg/mL exerts 77.67 and 38.51% protective effect against hypotonic solution and heat induced hemolysis, respectively. MEPA (250 and 500 mg/kg) produced 35.21 and 79.14% inhibition of acetic acid-induced writhing. Furthermore, MEPA (500 mg/kg) inhibited 49.19% early and 73.14% late phase of formalin-induced hypernociception. In contrast, a lower dose of MEPA did not prevent hot plate induced nociception, while in the tail immersion method, pronounced analgesic activity was observed between 1 and 4 h postdosing. The extract possesses significant in vitro antioxidant activity and a lipid peroxidation inhibition effect. Total phenolic and total flavonoid content in MEPA were 87.99 ± 0.87 mg GAE/g and 58.98 ± 0.01 mg QE/g, respectively.

DISCUSSION AND CONCLUSION

Our findings confirmed the analgesic, anti-inflammatory and antioxidant activities of Pisonia aculeata leaves. Contents of flavonoids and phenolic compounds in extract could be correlated with its observed biological activities.