Synthesis and bioactivity assessment of Coccinia grandis L. extract encapsulated alginate nanoparticles as an antidiabetic drug lead

AIM

This study aimed to prepare, characterise, and evaluate the antidiabetic activity of Coccinia grandis (L.) extracts encapsulated alginate nanoparticles.

METHODS

Alginate nanoparticles were prepared using the ionic gelation method and characterised by encapsulation efficiency %w/w, loading capacity %w/w, particle size analysis, zeta potential, Fourier transform infra-red spectroscopy (FTIR), and scanning electron microscopy (SEM). In vitro antidiabetic activity was also evaluated.

RESULTS

Encapsulation efficiency %w/w, loading capacity %w/w, mean diameter, zeta potential of C. grandis encapsulated alginate nanoparticles ranged from 10.51 ± 0.51 to 62.01 ± 1.28%w/w, 0.39 ± 0.04 to 3.12 ± 0.11%w/w, 191.9 ± 76.7 to 298.9 ± 89.6 nm, -21.3 ± 3.3 to -28.4 ± 3.4 mV, respectively. SEM and FTIR confirmed that particles were in nano range with spherical shape and successful encapsulation of plant extracts into an alginate matrix. The antidiabetic potential of aqueous extract of C. grandis encapsulated alginate nanoparticles (AqCG-ANP) exhibited inhibition in α-amylase, α-glucosidase and dipeptidyl peptidase IV enzymes of 60.8%c/c, 19.1%c/c, and 30.3%c/c, respectively, compared to the AqCG.

CONCLUSION

The AqCG-ANP exerted promising antidiabetic potential as an antidiabetic drug lead.

Bael (Aegle marmelos L. Correa) fruit extracts encapsulated alginate nanoparticles as a potential dietary supplement with improved bioactivities

Nanoencapsulated bael fruit (Aegle marmelos L. Correa (Family: Rutaceae)) extracts reveal novel prospects in the development of dietary supplements with improved biological activities in the field of the food industry. The main objectives of this study were to prepare and characterize aqueous, ethanol, 50% ethanol, and 50% acetone extracts of bael fruit encapsulated alginate nanoparticles and investigate the effect of encapsulation on in vitro release of polyphenols, antidiabetic, antioxidant, and anti-inflammatory activities, and their stability. Bael fruit extracts encapsulated alginate nanoparticles were prepared using the ionic gelation method. Characterization, in vitro release profiles of polyphenols, determination of antidiabetic, anti-inflammatory, antioxidant activity, and accelerated stability were conducted. The results of the characterization confirmed the successful encapsulation of extracts of bael fruit in the alginate matrix. The aqueous extract of bael fruit encapsulated alginate nanoparticles exhibited a more controlled slow-release profile, accounting for 21.82% ± 1.17% and 48.14% ± 0.52% of polyphenols at solutions of pH 1.2 and pH 6.8, respectively. In general, the results of the bioactivity assessment suggested that nanoencapsulation could facilitate the enhancement of its antidiabetic, antioxidant, and anti-inflammatory properties. The results of thermogravimetric analysis and thin layer chromatography fingerprint showed the stability of aqueous bael fruit extract encapsulated alginate nanoparticles at 27 and 4°C over a month. In summary, the results of this study revealed the potency of nanoencapsulated aqueous extract of bael fruit to develop a dietary supplement with improved antidiabetic, antioxidant, and anti-inflammatory activities. PRACTICAL APPLICATION: The encapsulation of bael fruit extracts into a nanocarrier enhances bioactivities and promotes the controlled release of bioactive compounds. This could be useful in the future food industry, based on scientifically proven data, and inspire the market by means of the development of dietary supplements. Overall, the results would facilitate the formulation of novel commercially elegant nanoencapsulated dietary supplements with improved potential to manage a healthy life.

Gastroprotective effect of Piper betle Linn. leaves grown in Sri Lanka

Background:

Piper betle Linn. (Piperaceae) is used as a remedy for gastric ulcers in traditional medicinal systems in Sri Lanka. However, the gastroprotective activity has never been proven scientifically using betel leaves grown in Sri Lanka.

Objective:

To evaluate the gastroprotective activity of hot aqueous extract (HAE) and cold ethanolic extract (CEE) of P. betle in rats as the experimental model.

Materials and Methods:

Three doses (200, 300, and 500 mg/kg/bw) of both extracts were evaluated for the gastroprotective activity against ethanol induced gastric ulcers in rats. The parameters evaluated were (a) effects of HAE on mucus content adhering to the wall of the gastric mucosa, (b) acidity (total and free), (c) volume and (d) pH of the gastric juice.

Results:

Oral administration of HAE and CEE provided marked dose dependent (HAE: r² = 0.97; CEE: r² = 0.96) and significant (P ≤ 0.05) protection against gastric damage caused by absolute ethanol. The gastroprotective effect of CEE was comparable with that of HAE. Further, gastroprotective activity of the highest dose of both extracts were significantly greater (P ≤ 0.05) than that of misoprostol, the reference drug. The HAE significantly (P ≤ 0.05) increased the mucus content adhering to the wall of the gastric mucosa and inhibited the volume of gastric acid. However, acidity (total and free) and pH of the gastric juice remained unaltered.

Conclusion:

It is concluded that both HAE and CEE of P. betle leaves have a strong gastroprotective activity.

Investigations on Piper betle grown in Sri Lanka

Piper betle is an economically important plant cultivated in Sri Lanka. Although more than 12 cultivars of betel are reported in Sri Lanka, very few scientific investigations have been carried out on them. Studies on the chemical constituents indicated that safrole is the major constituent, followed by chavibitol acetate, in the essential oil of common betel leaves of Sri Lanka. Investigations on the bioactivities of P. betle revealed the presence of antimicrobial, insecticidal, antioxidant, antinociceptive, antidiabetic and gastroprotective activities. In addition, P. betle was found to be safe in terms of hepatotoxicity, renotoxicity, hematotoxicity, gross morphology, weights of organs, stress or aversive behaviors in rats. The above findings indicate the vast potential of P. betle yet to be harnessed for the benefit of mankind and the betel industry of Sri Lanka.

Alpinia calcarata Roscoe: a potent antiinflammatory agent

AIM OF THE STUDY

Alpinia calcarata Roscoe (Family: Zingiberaceae) rhizomes are often used in Sri Lankan traditional systems of medicine as a remedy for bronchitis, cough, respiratory ailments, diabetics, asthma and arthritis. Generally drugs that are used for arthritis have antinociceptive and antiinflammatory properties. However, validity of the antiinflammatory activity has not been scientifically investigated so far. Therefore, the aim of this study was to investigate the antiinflammatory potential of Alpinia calcarata rhizomes using hot water extract (AWE) and hot ethanolic extract (AEE).

MATERIALS AND METHODS

The antiinflammatory activity of Alpinia calcarata was evaluated by use of the carrageenan-induced paw oedema model in rats. In addition, the mechanism/s by which Alpinia calcarata is mediated the antinflammatory activity was assessed by determining its effects on (a) membrane stabilizing, (b) antihistamine and (c) prostaglandin synthesis inhibition activity.

RESULTS

All the tested doses of AWE and AEE (250, 500, 750, and 1000 mg/kg) produced a significant (P≤0.05) inhibition of the inflammation, most pronounced at 4h after the injection of carrageenan. The antiinflammatory effect induced by 500 mg/kg of AEE was superior than the reference drug, indomethacin at 4h. Inhibition of histamine and prostaglandin synthesis production is probable mechanisms by which Alpinia calcarata mediates its antiinflammatory action.

CONCLUSION

These findings rationalize the traditional usage of Alpinia calcarata as an antiinflammatory agent for the first time.

Standardization of Alpinia calcarata Roscoe rhizomes

Background:

Rhizomes of Alpinia calcarata Roscoe (Family: Zingiberaceae) possess several bioactivities and are used in the traditional medicinal systems of Sri Lanka.

Methods:

The present investigation was carried out to standardize the rhizomes of A. calcarata by (a) screening for phytochemicals (b) determination of physico-chemical parameters and (c) development of a Densitogram.

Results:

Phytochemical screening revealed the presence of polyphenols, tannins, flavonoids, steroid glycosides and alkaloids in A. calcarata rhizomes. The percentages of moisture, total ash, acid insoluble ash, water soluble ash, ethanol extractable matter and water extractable matter were of 5.5 – 6.8, 8.3 – 8.8, 0.036 – 0.040, 7.2 – 7.8, 22.6 – 24.8 and 18.6 - 20.5 respectively.

Conclusion:

The results obtained from this study can be used to standardize rhizomes of A. calcarata grown in Sri Lanka.

Gastroprotective activity of Trichosanthes cucumerina in rats

AIM OF THE STUDY

The aim of the present study was to scientifically investigate whether Trichosanthes cucumerina Linn (Family: Cucurbitaceae) has gastroprotective activity.

MATERIALS AND METHODS

All the experiments were conducted using Wistar strain rats (weight: 200-220 g). The food and water given to rats was withdrawn for 36 and 12h respectively, before the commencement of the experiment. These rats were randomly divided into 6 groups (n=8 rats/group; 4 males+4 females) and groups 1-3 were orally administrated with hot water extract (HWE) at a dose of 375, 500 and 750 mg/kg, respectively. Group 4 was orally treated with equal volume of distilled water (1 mL; control), group 5 was orally treated with a reference drug, cimetidine (100mg/kg) while the group 6 was orally treated with another reference drug, sucralfate (400mg/kg). In the indomethacin experiment, only one dose of HWE (750 mg/kg) was tested, as this was found to have the maximum effect in the alcohol model also.

RESULTS

Results show that the HWE of Trichosanthes cucumerina possesses significant (P<or=0.05) and dose dependent gastroprotective effects in the alcohol model in terms of the length and number of gastric lesions mediated by alcohol, with a maximum effect at 750 mg/kg (inhibition of lesion length by 92%; number of gastric lesions by 88%). The same dose also mediated a significant (P<or=0.05) gastroprotective activity in the indomethacine model (inhibition of lesion length by 88%; number of gastric lesions by 84%). In both models, the protective effect demonstrated by the HWE was comparable with that produced by cimetidine. The HWE significantly (P<or=0.05) increased the amount of mucus produced by the rat gastro mucosa (by 39%) and reduced the gastric acidity (total acidity by 36%; free acidity by 40%). pH of the gastric juice increased from 4.1 to 6.0. However, no change in the volume of gastric juice was observed. Further, HWE showed potent antihistamine activity.

CONCLUSION

It may be concluded that HWE of Trichosanthes cucumerina exerts a significant protection against ethanol or indomethacin induced gastric damage. Increasing the protective mucus layer, decreasing the acidity of the gastric juice and antihistamine activity are probable mechanisms by which the HWE of Trichosanthes cucumerina mediates its gastroprotective actions.

Antidiabetic activities of aqueous and ethanolic extracts of Piper betle leaves in rats

Leaves of Piper betle (Piperaceae) possess several bioactivities and are used in traditional medicinal systems. However, its antidiabetic activity has not been scientifically investigated so far. The aim of this study therefore, was to investigate the antidiabetic activity of Piper betle leaves. This was tested in normoglycaemic and strepozotocin (STZ)-induced diabetic rats using oral administration of hot water extract (HWE) and cold ethanolic extract (CEE). In normoglycaemic rats, both HWE and CEE significantly lowered the blood glucose level in a dose-dependent manner. In glucose tolerance test, both extracts markedly reduced the external glucose load. The antidiabetic activity of HWE is comparable to that of CEE. Moreover, HWE failed to inhibit the glucose absorption from the small intestine of rats. Both extracts were found to be non-toxic and well tolerated after following chronic oral administration (no overt signs of toxicity, hepatotoxicity or renotoxicity). However, the weight of the spleen had increased in treated groups possibly indicating lymphoproliferative activity. It is concluded that HWE and CEE of Piper betle leaves possess safe and strong antidiabetic activity.

Antinociceptive activities of aqueous and ethanolic extracts of Alpinia calcarata rhizomes in rats

Rhizomes of Alpinia calcarata Roscoe (Zingiberaceae) posses several bio-activities and are used in traditional medicine of Sri Lanka. However, their antinociceptive activity has not been investigated so far. The aim of this study therefore, was to examine the antinociceptive activity of hot water extract (HWE) and hot ethanol extract (HEE) of Alpinia calcarata rhizomes using rats and three models of nociception (tail flick, hot plate and formalin tests). Different concentrations of HWE (100, 250, 500, 750, 1000 mg/kg) and HEE (100, 250, 500, 750, 1000 mg/kg) were made and orally administrated to rats and the reaction times determined. The results showed that the extracts have marked dose-dependent antinociceptive activity, when evaluated in the hot plate and the formalin tests but not in the tail flick test. The antinociceptive effect was slightly higher in HEE than that of HWE. The antinociceptive effect was mediated via opioid mechanisms.