Phytochemical analysis, in vitro and in silico effects from Alstonia boonei De Wild stem bark on selected digestive enzymes and adipogenesis in 3T3-L1 preadipocytes

BACKGROUND

Obesity is a global health issue arising from the unhealthy accumulation of fat. Medicinal plants such as Alstonia boonei stem bark has been reported to possess body weight reducing effect in obese rats. Thus, this study sought to investigate the in vitro and in silico effects of fractions from Alstonia boonei stem bark on selected obesity-related digestive enzymes and adipogenesis in 3T3-L1 preadipocytes.

METHOD

Two fractions were prepared from A. boonei: crude alkaloid fraction (CAF) and crude saponin fraction (CSF), and their phytochemical compounds were profiled using Liquid chromatography with tandem mass spectrometry (LCMS/MS). The fractions were assayed for inhibitory activity against lipase, α-amylase and α-glucosidase, likewise their antiadipogenic effect in 3T3-L1 adipocytes. The binding properties with the 3 enzymes were also assessed using in silico tools.

RESULTS

Eleven alkaloids and six saponin phytochemical compounds were identified in the CAF and CSF using LCMS/MS. The CAF and CSF revealed good inhibitory activity against pancreatic lipase enzyme, but weak and good activity against amylase respectively while only CSF had inhibitory activity against α-glucosidase. Both fractions showed antiadipogenic effect in the clearance of adipocytes and reduction of lipid content in 3T3-L1 adipocytes. The LCMS/MS identified compounds (41) from both fractions demonstrated good binding properties with the 3 enzymes, with at least the top ten compounds having higher binding energies than the reference inhibitors (acarbose and orlistat). The best two docked compounds to the three enzymes were firmly anchored in the substrate binding pockets of the enzymes. In a similar binding pattern as the reference acarbose, Estradiol-17-phenylpropionate (-11.0 kcal/mol) and 3α-O-trans-Feruloyl-2 α -hydroxy-12-ursen-28-oic acid (-10.0 kcal/mol) interacted with Asp197 a catalytic nucleophile of pancreatic amylase. Estradiol-17-phenylpropionate (-10.8 kcal/mol) and 10-Hydroxyyohimbine (-10.4 kcal/mol) interacted with the catalytic triad (Ser152-Asp176-His263) of pancreatic lipase while Estradiol-17-phenylpropionate (-10.1 kcal/mol) and 10-Hydroxyyohimbine (-9.9 kcal/mol) interacted with Asp616 and Asp518 the acid/base and nucleophilic residues of modelled α-glucosidase.

CONCLUSION

The antiobesity effect of A. boonei was displayed by both the alkaloid and saponin fractions of the plant via inhibition of pancreatic lipase and adipogenesis.

and Its Constituents: Ex Vivo and In Silico Approaches

BACKGROUND

Alstonia boonei, belonging to the family Apocynaceae, is one of the best-known medicinal plants in Africa and Asia. Stem back preparations are traditionally used as muscle relaxants. This study investigated the antispasmodic properties of Alstonia boonei Stem back and its constituents.

METHOD

The freeze-dried aqueous Stem back extract of A. boonei, as well as dichloromethane (DCM), ethyl acetate, and aqueous fractions, were evaluated for their antispasmodic effect via the ex vivo method. Two compounds were isolated from the DCM fraction using chromatographic techniques, and their antispasmodic activity was evaluated. An in silico study was conducted by evaluating the interaction of isolated compounds with human PPARgamma-LBD and human carbonic anhydrase isozyme.

RESULTS

The Stem back crude extract, DCM, ethyl acetate, and aqueous fractions showed antispasmodic activity on high-potassium-induced (K+ 80 mM) contractions on isolated rat ileum with IC50 values of 0.03 ± 0.20, 0.02 ± 0.05, 0.03 ± 0.14, and 0.90 ± 0.06 mg/mL, respectively. The isolated compounds from the DCM fraction were β-amyrin and boonein, with only boonein exhibiting antispasmodic activity on both high-potassium-induced (IC50 = 0.09 ± 0.01 µg/mL) and spontaneous (0.29 ± 0.05 µg/mL) contractions. However, β-amyrin had a stronger interaction with the two proteins during the simulation.

CONCLUSION

The isolated compounds boonein and β-amyrin could serve as starting materials for the development of antispasmodic drugs.

leaves ameliorate oxidative stress and modulate key hypoglycaemic processes in diabetic rats

OBJECTIVE

The effect of Alstonia boonei fractions on glucose homeostasis was investigated via in vitro enzyme inhibition activity, ex vivo glucose uptake assay, and in vivo methods in diabetic rats.

METHODOLOGY

A. boonei fractions were subjected to in vitro α-glucosidase inhibitory assay and then ex vivo glucose uptake activity. The butanol fraction of the leaves (ABBF) was picked for the in vivo assay since it showed more activity in the initial tests conducted. ABBF was administrated via oral dosing to six-weeks old fructose-fed STZ-induced type 2 diabetic rats over a 5-week experimental period.

RESULTS

ABBF treatment at a low dose of 150 mg/kg bw, significantly (p < .05) reduced blood glucose level, enhanced oral glucose tolerance ability, restored insulin secretion and hepatic glycogen synthesis as well as promoted islet regeneration than the high dose (300 mg/kg bw).

CONCLUSION

These results suggest that ABBF could be exploited as a therapeutic potential for treating T2D.

Comparative in vivo antimalarial activities of aqueous and methanol extracts of MAMA powder - A herbal antimalarial preparation

ETHNOPHARMACOLOGICAL RELEVANCE

The choice of extraction solvent is a significant consideration in ethnomedicine as optimal extraction could influence the bioactivity of the herbal medicinal product.

AIM OF STUDY

This study investigated the possible influence of the choice of solvents (methanol and water) for extracting MAMA Powder (MP) against Plasmodium berghei-infected mice to optimize its antimalarial activity and for developing other pharmaceutical dosage forms.

MATERIALS AND METHODS

Aqueous and methanol extracts of MP, obtained through the decoction and soxhlet methods, respectively, were subjected to liquid chromatography-mass spectroscopy (LC-MS) for their respective fingerprints. The antimalarial activities of the methanol and aqueous extracts (12.5-100 mg/kg) were evaluated orally using the chemosuppressive test model on chloroquine-sensitive Plasmodium berghei-infected mice. The methanol extract was subjected to the established infection and prophylactic antimalarial tests with chloroquine (10 mg/kg) and pyrimethamine (1.25 mg/kg) as positive controls, respectively. The aqueous extract was investigated in chloroquine-resistant P. berghei using the chemosuppressive (12.5-800 mg/kg) and established infection (25-400 mg/kg) antimalarial models.

RESULTS

The LC-MS fingerprints of both aqueous and methanol extracts revealed similar indole alkaloid contents. Chemosuppressive activity of the aqueous extract (75.3%) was significantly (p < 0.05) higher than the methanol extract (67.6%). In the chloroquine-resistant P. berghei infection experiments, the aqueous extract (400 mg/kg) exhibited significant parasite clearance (72%).

CONCLUSION

The study concluded that the water extract with higher antimalarial activity could be optimized for chloroquine-resistant malaria and can thus facilitate the production of liquid and solid dosage forms.

Anti-Inflammatory Potentials of the n-Hexane Fraction of Alstonia boonei Stem Bark in Lipopolysaccharide-Induced Inflammation in Wistar Rats

Background

Inflammation is a protective response of the host to infections and tissue damage and medicinal plants have been used to regulate inflammatory response. The phytochemical contents of the n-hexane fraction of Alstonia boonei and their anti-inflammatory potentials in lipopolysaccharide-induced inflammation were investigated in rat liver.

Materials and Methods

A quantity of 5 mg/kg lipopolysaccharide (LPS) was used to induce inflammation in twenty-five male Wistar rats, grouped (n = 5) and treated as follows: negative control (10 mL/kg saline), positive control (1 mg/kg ibuprofen); 50, 100 and 20 mg/kg of the n-hexane fraction of Alstonia boonei were administered to test groups. In another experiment, twenty rats (n = 5, without LPS) were administered the same doses of the n-hexane fraction of A. boonei and ibuprofen for seven days. At the end of the experiment, animals were sacrificed, serum was obtained from blood and liver mitochondria isolated in a refrigerated centrifuge. Mitochondrial permeability transition (mPT) pore opening and mitochondrial F₀F₁ ATPase (mATPase) were determined spectrophotometrically. Serum interleukins 1β, 6 (IL-1β, IL-6), tumour necrosis factor alpha (TNF-α), C-reactive protein (CRP) and creatine kinase (CK), gamma glutamyl transferase (GGT), aspartate and alanine aminotransferases (AST and ALT,) of the animals in which inflammation was induced using LPS but treated with graded doses of n-hexane fraction of A. boonei were determined using the ELISA technique. The phytochemical contents of the n-hexane fraction of A. boonei were determined using ultra performance liquid chromatography-tandem mass spectrometer (UHPLC-MS).

Results

Calcium induced mPT in 8 fold and LPS induced mPT 14 fold in the negative control while the n-hexane fraction reversed mPT in the treated groups (50, 100 and 200 mg/kg) to 2, 4, 4 folds, respectively. LPS treatment of the negative group enhanced F₀F₁ mATPase activity, increased CRP, TNF-α, IL-1β, IL-6 levels as well as CK, AST, ALT and GGT activities. These values were significantly reduced by 100 and 200 mg/kg of the n-hexane fraction. UHPLC-MS analysis of the fraction revealed the presence of terpenoids, phenolics and sphingolipids.

Conclusion

These results showed that bioactive phytochemicals present in the n-hexane fraction of A. boonei were not toxic, have an anti-inflammatory effect and could be used for the treatment of inflammatory diseases.

In vitro screening of plant extracts traditionally used as cancer remedies in Ghana - 15-Hydroxyangustilobine A as the active principle in Alstonia boonei leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Cancer represents a major health burden and drain on the global healthcare systems. Traditional African medicine widely use a variety of plant species for treatment of different kinds of cancer. A previous systematic survey by traditional healers in the Ashanti region of Ghana revealed a good overview on the plant species and herbal materials used for the different types of cancer.

AIMS OF THE STUDY

The following study aimed to investigate 18 herbal materials from 10 plant species based on the cancer survey in Ghana regarding potential cytotoxicity against different cancer cell lines under in vitro conditions followed by subsequent bioassay-guided fractionation towards the active principle.

MATERIALS AND METHODS

Ethanol-water (1:1) extracts were tested (1-100 μg/mL) against a panel of cancer cell lines according to their respective traditional use. Selected extracts with relevant cytotoxicity in this screening were also tested against common pediatric malignancies (leukemias (HL-60, REH) and Ewing sarcoma (RD-ES and CADO-ES1)). Bioassay-guided fractionation of the hydroalcoholic extract from Alstonia boonei was performed by liquid-liquid chromatography and preparative HPLC. Preliminary mechanistic studies on the mode of action were performed by flow cytometric cell cycle analysis as well as apoptosis and necrosis staining.

RESULTS

Screening of plant extracts revealed relevant cytotoxicity against all tested cancer cell lines for Alstonia boonei leaves and stem of Paulinia pinnata. The A. boonei extract was additionally found to be active against common pediatric tumor types (leukemias and Ewing sarcoma). Bioassay-guided fractionation of the A. boonei extract revealed the presence of 15-hydroxyangustilobine A 1 as the active principle (IC₅₀ 26 μM against MCF-7 cells). This is the first report of this compound in A. boonei. 1 was shown to lead to cell cycle arrest in the G2/M-phase (MCF-7 cells), triggering cells at least partially into apoptosis.

CONCLUSION

In summary, an appreciable in vitro activity was revealed for the leaf extract from A. boonei and the isolated vallesamine type indole alkaloid 1, which has to be investigated in future studies towards a potential clinical use.

In vivo studies on the biochemical indices of Plasmodium berghei infected mice treated with Alstonia boonei leaf and root extracts

BACKGROUND

A study on the biochemical indices of albino mice infected with Plasmodium berghei and treated with Alstonia boonei aqueous and ethanolic extracts was undertaken.

METHODS

216 males mice were randomly assigned to six treatment groups each containing six mice for both aqueous and ethanolic extracts experiments. P. berghei NK-65 was inoculated into the mice intraperitoneally and establishment of infection confirmed. Administration of extracts of was done after phytochemical and acute toxicity tests at varying concentrations, for both suppressive and curative tests. Blood samples collected by ocular puncturing were examined for the biochemical indices; ALT, AST, ALP, creatinine and total protein using the standard procedures.

RESULTS

A. boonei extracts suppression of P. berghei in mice was comparable to the standard drug. Significantly higher (p<0.05) recovery of mice treated with A. boonei extracts was observed. The biochemical indices examined all had significantly (p<0.05) increased concentration after 7 days post-infection, except for total protein concentration which had no significant increase or decrease due to A. boonei extracts administration.

CONCLUSION

The antiplasmodial potentials of A. boonei leaf and root extracts were dosage and duration-dependent, and have demonstrated satisfactory normalization of altered biochemical indices due to malaria.

Aqueous fraction of Alstonia boonei de Wild leaves suppressed inflammatory responses in carrageenan and formaldehyde induced arthritic rats

Alstonia boonie de Wild is an ethnomedical plant used as therapy against inflammatory disorders. This study evaluated the most active anti-inflammatory and anti-oxidant fraction of A. boonei leaves using in vitro and in vivo models. Quantitative phytochemical analysis, anti-protein denaturation and hypotonicity-induced hemolysis of human red blood cell membrane (HRBC), radical scavenging activity assays, carrageenan and formaldehyde-induced inflammation models were carried out. Results showed that aqueous and ethyl acetate fractions of 70% methanol extract of A. boonie leaves contained high quantities of total phenolic and flavonoid compounds compared with hexane and butanol fractions. Aqueous fraction of A. boonie leaves significantly (P<0.05) inhibited heat-induced protein denaturation, stabilized hypotonicity-induced hemolysis of HRBC, scavenged DPPH, NO and H₂O₂ radicals in a concentration-dependent manner compared with other fractions in vitro. In addition, orally administered 50-250-mg/kg body weight (b.w.) aqueous fraction of A. boonei leaves suppressed carrageenan-induced rat paw edema thickness by 74.32%, 79.22% and 89.86% respectively at 6th h in a dose-dependent manner comparable with animals treated with standard diclofenac sodium (88.69%) in vivo. Furthermore, investigation of formaldehyde-induced inflammation in rats showed that 50-250 mg/kg b.w. aqueous fraction of A. boonei reduced plasma alanine aminotransferase and aspartate aminotransferase activities. Aqueous fraction of A. boonei also suppressed eosinophils, monocytes and basophils, total white blood cell, total platelet, neutrophil and lymphocyte counts and modulated plasma lipid profile compared with control group. Aqueous fraction of A. boonei leaves exhibited substantial active anti-inflammatory and antioxidant activities. Hence, an aqueous fraction of A. boonei leaves could be channeled towards pharmaceutical drug development. In addition, this study provided scientific insight to account for the traditional use of A. boonei leaves in ethnomedical practice.

In vivo anti-plasmodial activities and toxic impacts of lime extract of a combination of Picralima nitida, Alstonia boonei and Gongronema latifolium in mice infected with Chloroquine-sensitive Plasmodium berghei

BACKGROUND

Lime extracts of powdered combination of seeds of Picralima nitida, stem bark of Alstonia boonei and leaves of Gongronema latifolium is a common remedy used in the treatment of malaria in South Western Nigeria.

OBJECTIVE

To determine the antiplasmodial activities of the combined herbal extracts and its impact on the haematological, hepatological and renological parameters in mice.

METHODS

The 4-day suppressive and curative tests were used to assess the antiplasmodial activities of the extract in mice infected with chloroquine-sensitive Plasmodium berghei at concentration of 200mg/kg, 400mg/kg and 800mg/kg body weight. The haematological parameters including red blood cells, white blood cells, packed cell volume and haemoglobin count were analysed with an auto analyser. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were determined, while urea, protein and creatinine were analysed by standard procedural methods.

RESULTS

The 4-day suppressive test revealed that the test extract achieved percentage suppression of 39.0%, 41.6% and 54.68% for the 200mg/kg, 400mg/kg and 800mg/kg concentration respectively. Additionally, the curative test achieved a high percentage suppression of 80.97%, 83.84% and 86.16% at the 200mg/kg, 400mg/kg and 800mg/kg concentration respectively. The extracts did not induce significant change on haematological parameters (P>0.05), while significant elevation in the values of the ALT and AST (P<0.05) was observed and elevation of creatinine (P<0.05) at 800mg/kg.

CONCLUSIONS

The results support the traditional use of the herbal combination in the treatment of malaria, however the liver cells were impacted by the extracts in bioassay conducted with mice.