Biosynthesis of copper nanoparticles using Alstonia scholaris leaves and its antimicrobial studies

The utilization of plants for the production of metallic nanoparticles is gaining significant attention in research. In this study, we conducted phytochemical screening of Alstonia scholaris (A. scholaris) leaves extracts using various solvents, including chloroform, ethyl acetate, n-hexane, methanol, and water. Our findings revealed higher proportions of flavonoids and alkaloids in both solvents compared to other phytochemical species. In the methanol, extract proteins, anthraquinone and reducing sugar were not detected. On the other hand, the aqueous extract demonstrated the presence of amino acids, reducing sugar, phenolic compounds, anthraquinone, and saponins. Notably, ethyl acetate and chloroform extracts displayed the highest levels of bioactive compounds among all solvents. Intrigued by these results, we proceeded to investigate the antibacterial properties of the leaf extracts against two major bacterial strains, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). All extracts exhibited significant zones of inhibition against both bacterial isolates, with S. aureus showing higher susceptibility compared to E. coli. Notably, the methanol extract displayed the most potent I hibitory effect against all organisms. Inspired by the bioactivity of the methanol extract, we employed it as a plant-based material for the green synthesis of copper nanoparticles (Cu-NPs). The synthesized Cu-NPs were characterized using Fourier infrared spectroscopy (FT-IR), UV-visible spectroscopic analysis, and scanning electron microscopy (SEM). The observed color changes confirmed the successful formation of Cu-NPs, while the FTIR analysis matched previously reported peaks, further verifying the synthesis. The SEM micrographs indicated the irregular shapes of the surface particles. From the result obtained by energy dispersive X-ray spectroscopic analysis, Cu has the highest relative abundance of 67.41 wt%. Confirming the purity of the Cu-NPs colloid. These findings contribute to the growing field of eco-friendly nanotechnology and emphasize the significance of plant-mediated approaches in nanomaterial synthesis and biomedical applications.

Effects of total alkaloids from Alstonia scholaris (L.) R. Br. on ovalbumin-induced asthma mice

ETHNOPHARMACOLOGICAL RELEVANCE

More than 300 million people worldwide suffer from asthma, a chronic respiratory inflammatory disease. Total alkaloids (TA) were extracted from the ethnic medicinal plant Alstonia solaris (L.) R.Br., which is used to treat respiratory diseases. They may be effective drugs for treating asthma, but research is still needed to determine their effectiveness and mechanism in treating asthma.

AIM OF THE STUDY

To further understand TA's role in the treatment of asthma and to support the phase II trial of the drug.

MATERIALS AND METHODS

In this study, we investigated the effects of TA in a mouse asthma model produced by Ovalbumin (OVA). H&E and PAS staining were used to observe the histopathological features of lung. airway hyperresponsiveness (AHR) was detected by ventilator; The expression of interleukin (IL)-33, suppression of tumorigenicity 2 (ST2) and E-cadherin in the lungs was evaluated by IHC. The concentrations of Mucin5AC (MUC5AC), eotaxin, IL-4, IL-5, IL-9, IL-13, interferon (IFN)-γ, IL-6, IL-8, IL-17A, IL-33, IL-25, thymic stromal lymphopoietin (TSLP), monocyte chemoattractant protein 1 (MCP-1), leukotriene (LT) B4, LTC4, LTD4, LTE4 in bronchoalveolar lavage fluid (BALF) and total IgE (tIgE), OVA-Specific IgE (OVA-IgE) in serum were measured by ELISA. ILC2s and eosinophils were detected in lung tissue by flow cytometry. The gene expression levels of IL-33 and ST2 were detected by RT-qPCR.

RESULTS

Administration of TA reduced pulmonary inflammatory symptoms, MUC5AC production in the BALF, and AHR. At the same time, TA inhibited eotaxin production and eosinophil recruitment. Moreover, TA significantly decreased Th2 and Th17 cytokines and increased Th1 cytokines, contributing to restore the balance between Th1 and Th2 and Th17 cytokines. TA may reduce ILC2s numbers by inhibiting IL-33, IL-25, and TSLP levels in BALF and IL-33/ST2 signaling in lung tissue. Finally, TA decreased tIgE, OVA-IgE, and MCP-1 levels and subsequently inhibited mast cell activation and leukotriene release.

CONCLUSIONS

These findings imply that TA may be an effective immunoregulatory medication for the management and prevention of asthma.

Butanol fraction of Alstonia boonei De Wild. 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.

Neuroprotection by Alstonia boonei De Wild., Anacardium occidentale L., Azadirachta indica A.Juss. and Mangifera indica L

ETHNOPHARMACOLOGY RELEVANCE

Alstonia boonei De Wild. (stem bark), Anacardium occidentale L. (stem bark), Azadirachta indica A.Juss (leaves), Enantia chlorantha Oliv. (stem bark), Khaya senegalensis A.Juss (stem bark) Mangifera indica L. (stem bark), and Nauclea latifolia Sm. (stem bark) are used for treating malaria in southwest Nigeria. Surveys revealed that these plants are also employed for treating symptoms of malaria and cerebral malaria in the region.

AIM OF THE STUDY

In this study, the effects of freeze-dried extracts of these plants were investigated on synthetic hemozoin (HZ)-induced neuroinflammation, neuronal damage, and increased permeability of brain microvascular endothelial cells.

MATERIALS AND METHODS

Effects of freeze-dried plant extracts were investigated on neuroinflammation by measuring levels of pro-inflammatory mediators in culture supernatants, while in-cell western assays were used to measure protein levels of iNOS and NLRP3. Effects on HZ-induced neurotoxicity and ROS generation was measured using MTT and DCFDA assays, respectively. HZ-induced permeability of hCMEC/D3 endothelial cells was determined using the in vitro vascular permeability assay kit.

RESULTS

The extracts produced significant (p < 0.05) reduction in TNFα, IL-6, IL-1β, MCP-1, RANTES and iNOS/NO production in HZ-stimulated BV-2 microglia. Pre-treatment with 50 μg/mL of A. boonei, A. indica, A. occidentale, E. chlorantha and M. indica also resulted in the inhibition of NF-κB activation. Pre-treatment with A. indica produced, A. occidentale, M. indica and A. boonei reduced HZ-induced increased NLRP3 protein expression. HZ-induced increased caspase-1 activity was also reduced by A. boonei, A. occidentale, A. indica, E. chlorantha, and M. indica. Freeze-dried extracts of A. boonei, A. occidentale, A. indica and M. indica produced neuroprotective effect in HT-22 neuronal cells incubated with HZ by preventing HZ-induced neurotoxicity, ROS generation, DNA fragmentation and caspase 3/7 activity. Inhibition of HZ-induced increase in permeability of human hCMEC/D3 brain endothelial cells was also observed with A. boonei, A. occidentale, A. indica and M. indica, while reducing the release of TNFα and MMP-9.

CONCLUSIONS

These results suggest that A. boonei, A. occidentale, A. indica and M. indica are neuroprotective through inhibition of neuroinflammation, neuronal damage and increased permeability of blood brain barrier. The outcome of the study provides pharmacological evidence for the potential benefits of plants as herbal treatments for cerebral malaria symptoms.

Low-temperature synthesis of functionalized activated carbon from blackboard (Alstonia scholaris) with improved selectivity for 2-methylpyridine removal: batch and column analyses

Coal tar industry has been reported to discharge 2-methylpyridine (2Mp) in concentrations up to 150 mg L^-1. For removal of 2Mp, activated carbon was synthesized from blackboard tree ground bark (BA) by the novel technique of prior cooling (which helped decrease heat generation and volatile gas emission). The material was successfully functionalized with carboxylic group which enhanced 2Mp uptake. Batch sorption of 2Mp was carried out on both BA and carboxyl functionalized BA (CFA). Acetonitrile-water (55:45) was used as eluent in uHPLC quantification of 2Mp. Interaction mechanism of 2Mp with both sorbents was studied by using characterization techniques (SEM, FTIR and EDS). Carboxyl groups present on CFA were found to interact with 2Mp molecules, leading to their removal from synthetic solution. Carboxylation helped in lowering the intrinsic moisture content of the sorbent. Proton leaching from carboxyl groups of CFA was found to be negligible. Specific surface areas for CFA and BA were found as 211.15 m² g^-1 and 156.32 m² g^-1, respectively. Batch experimentation showed that CFA had twice the adsorption capacity compared to BA (27.0 and 15.5 mg g^-1, respectively). Pseudo-second-order kinetics and Langmuir isotherm-based equilibria were observed. Intraparticle diffusion was the rate-limiting step. Top-down fixed bed studies were performed using a 2-cm-diameter column by varying flow rate, bed depth and 2Mp concentration, respectively. The Thomas model could successfully emulate the steep slopes of the breakthrough curves, implying good sorbent saturation.

Macroline, talpinine, and sarpagine alkaloids from Alstonia penangiana. An NMR-based method for differentiating between A. penangiana and A. macrophylla

Fourteen previously undescribed alkaloids comprising two N-1-hydroxymethylmacroline alkaloids, one talpinine-type oxindole acetal, a pair of equilibrating talpinine-type oxindole hemiacetals, eight oxidized derivatives of sarpagine- and akuammiline-type indole alkaloids, in addition to alstochalotine a diastereomer of gelsochalotine recently isolated from Gelsemium elegans, were isolated from the leaf and stem-bark extracts of Alstonia penangiana. The structures and relative configurations of these alkaloids were established using NMR, MS, and in one instance, confirmed by X-ray diffraction analysis. An NMR-based method is described as a useful chemotaxonomic tool for differentiating between A. penangiana and A. macrophylla. Several of the alkaloids isolated showed appreciable growth inhibitory effects when tested against a number of human cancer cell lines.

In vitro and in vivo antiplasmodial activity of extracts and isolated constituents of Alstonia congensis root bark

ETHNOPHARMACOLOGICAL RELEVANCE

An aqueous decoction of root bark of Alstonia congensis Engl. (Apocynaceae) is used in several African countries to treat various ailments including malaria.

MATERIALS AND METHODS

Extracts of different polarity and isolated constituents were tested in vitro for their antiplasmodial activity against the chloroquine-resistant strain Plasmodium falciparum K1 and the chloroquine-sensitive strain P. falciparum NF54A19A, as well as for their cytotoxic effects againt MRC-5 cells (human lung fibroblasts). Extracts and fractions were evaluated in vivo against the chloroquine-resistant strain P. yoelii N67 and the chloroquine-sensitive strain P. berghei berghei ANKA.

RESULTS

The aqueous extract, the 80% methanol extract and the alkaloid-enriched extract exhibited strong antiplasmodial activity against P. falciparum K1 with IC₅₀ values < 10 µg/ml and against P. falciparum NF54 A19A with IC₅₀ values < 0.02 µg/ml. In vivo against P. yoelii N67, at the highest oral dose of 400 mg/kg body weight, all extracts produced 70-73% chemosuppression, while against P. berghei berghei, more than 75% chemosuppression was observed. With regard to the isolated constituents, boonein was inactive in vitro against P. falciparum K-1 (IC₅₀ > 64 µM), while echitamine, 6,7-seco-angustilobine B and β-amyrin exhibited moderate activity (IC₅₀ < 30 µM). Against P. falciparum NF54 A19A, boonein was inactive (IC₅₀ > 64 µM), while echitamine, 6,7-secoangustilobine and β-amyrin showed moderate IC₅₀ values of 11.07, 21.26 and 40.70 µM, respectively.

CONCLUSION

These results demonstrated that all extracts from A. congensis root bark possessed antiplasmodial activity in vitro and in vivo. They can be used as raw materials for the preparation of ameliorated remedies for the treatment of uncomplicated malaria. The observed antiplasmodial activity may be due in part to the presence of indole alkaloids.

Effects of indole alkaloids from leaf of Alstonia scholaris on post-infectious cough in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Leaf of Alstonia scholaris (L.) R. Br. (Apocynaceae), a wide used ethic-medicine in many Asia and Africa counties, has also been recorded as the common traditional Chinese medicine for treatment of illnesses in respiratory system by Dai people.

AIM OF THE STUDY

To provide experimental data of clinical adaption of total indole alkaloids (TA) from leaf of A. scholaris for treating post-infectious cough in phase II clinical trial.

MATERIALS AND METHODS

To model post-infectious cough, all animals except control group were instilled intra-tracheal with lipopolysaccharide (LPS) (80 μg/50 µL/mouse), followed by subsequent exposure to cigarette smoke (CS) for 30 min per day for a total of 30 days. Mice were orally given TA at dose of 10, 25, 50 mg/kg, and four main alkaloids (Sch: scholaricine, Epi: 19-epischolaricine, Val: vallesamine, Pic: picrinine) once daily. Cellular infiltration was assessed in the broncho-alveolar lavage fluid (BALF). Expression of interleukin-6 (IL-6) and C-reactive protein (CRP) in the serum was determined, the superoxide dismutase (SOD) activity as well as malondialdehyde (MDA) content in the serum and homogenate were examined. Finally, histopathological examination in the lungs was assessed by H. E. staining.

RESULTS

After administration of TA and four major alkaloids respectively, the symptoms of cough in mice were obviously attenuated. Total white blood cells (WBC) and neutrophils (NEU) amounts in BALF were reduced obviously and the pathological damage of lung was also attenuated. There was also significant reduction in IL-6, CRP, MDA and a marked improvement in SOD.

CONCLUSIONS

The efficacy of indole alkaloids against post-infectious cough (PIC) was shown in the down-regulation of inflammatory cells, cytokines, and the balance of antioxidants. What's more, the pharmacological effects of TA were better than single indole alkaloid, which might be related to the synergic effect of four major alkaloids.

[Application of FTIR and Active Ingredients Quantitative Analysis on Quality Control of Dai Medicine Alstonia scholaris (L.) R. Br.]

FTIR fingerprint of the leaves and immature stems of Alstonia scholaris (L.) R. Br. was established as a content determination method for the detection of picrinine, ursolic acid and oleanolic acid. Different medicinal parts were identified based on principal component analysis, while exploring the influence of immature stems for the leaves and the application of FTIR and HPLC in the Dai quality control in order to speed up the pace of Dai medicine modernization. Infrared spectroscopy of different batches samples were collected and the data was preprocessed as to automatic baseline correction, smooth, ordinate normalization, second order derivative, and then to PCA, all the datum in triplicate. For content determination of picrinine, mobile phase was acetonitrile (40) water (contain 0.1% ammonia water) (60) and the wavelength was set at 287 nm. For ursolic acid and oleanolic acid, the mobile phase was mixture (12∶88) of 0.1% formic acid in water (A) and methanol (B). Wavelength was 210 nm. As the results, the original spectrum difference was not obvious for leaves and stems. Pretreatment spectroscopy had a significant variation on absorption peak number and intensity in 3 000～2 800 and 1 800～500 cm(-1). The results of PCA showed that, the leaves and stems were separated; in addition the difference of different batches leaves was bigger than the stems. The mean contents of picrinine, ursolic acid and oleanolic acid in leaves were 0.79，8.47，7.51 and 0.21，1.78，1.67 mg·g(-1) in stems, respectively. The content of ursolic acid and oleanolic acid is higher than picrinine, but ursolic acid and oleanolic acid content had no obvious difference. Mean content of three ingredients in leaves is much higher than in stems. Picrinine content in leaves was 3.8 times of immature stems, ursolic acid and oleanolic acid content were 5.1 and 4.2 times of immature stems, respectively. The variety of picrinine content in different batches samples was biggest, ursolic acid and oleanolic acid content was relatively stable. The overall quality of leaves has an obvious difference compared with the immature stems, so the leaves of A. scholaris mix with immature stems could not be as Dai medicine in Dai clinic. Infrared spectroscopy combined with chromatography can quickly identify different medicinal parts and evaluate overall quality of Dai medicine, which can apply to quality control of Dai medicine.

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.

[Distinguish and Quality Estimation of the Leaves of Alstonia scholaris (L.) R. Br. from Different Harvest Time Based on the UV-Vis·FP and HPLC·FP]

UV-Vis and HPLC fingerprint of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. were establish the for identification and quality evaluation to promote the development of Dai Medicine modernization. The optimal extraction condition was used to obtain UV - vis data of different harvest time which were deducted background and eight spot smooth, were collected to make the principal component analysis in SIMCA-P(+)11.5, identifying the samples quickly with the first three principal component three-dimensional diagram. The HPLC fingerprint were obtained with Agilent ZORBAX Eclipse XDB C18 (250×4.6 mm, 5 μm) chromatographic column with the mobile phase of acetonitrile (B) - water (contain 0.1% formic acid) (A) for gradient elution (0～5 min, 5% B; 5～35 min, 5% B→26% B; 35～40 min, 26% B→56% B). The wavelength was set at 287 nm and the column temperature was maintained at 30 ℃. The flow rate was 1.0 mL·min-1 and the injection volume was 7 μL. The HPLC fingerprint of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. was analysised by cluster analysis to quality evaluation. Research findings showing: (1) The UV-Vis spectrogram of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. were divided into three parts according to the absorption peak position and amplitude of variation. The first was 235 to 400 nm, the second was 400 to 500 nm, and the third was 500 to 800 nm. In the first part, absorption peak were focused on 270, 287 and 325 nm, which can reflect the fingerprint character for the high absorbance and amplitude of variation. Absorption peak were distributed in 410 and 464 nm in the second part, absorbance and amplitude of variation were lower than the first part. There was a bigger absorption peak at 665 nm in the third part, but the absorbance had no difference. The UV-Vis data of different harvest time were gathered to make the principal component analysis, the result was that the samples of same month were concentrated distribution, but different month samples were dispersed distribution. (2) HPLC fingerprint were divided into three categories through hierarchical cluster analysis, 3, 4, 5 and 7 month were the first category, 6, 8, 9 month samples were second category, the others were third category. Chemical composition and content of the same category samples were similar, but the different category samples had a obvious difference, more important is that the third category samples content was the highest. Combining UV-Vis FP and HPLC FP can identify and evaluate quickly the samples of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. The optimal harvest time of Alstonia scholaris (L.) R. Br. was from October to next February, which was the coldest season in the Dai calendar.

Mechanisms underlying the antihypertensive effect of Alstonia scholaris

ETHNOPHARMACOLOGICAL RELEVANCE

Alstonia scholaris has a long history of use in the Ayurveda traditional treatment of various ailments including hypertension. We have reported the blood pressure lowering activity of the extract of A. scholaris. The following research aim to delineate the pharmacological mechanism involve in the antihypertensive action.

MATERIALS AND METHOD

Vasorelaxant effect of the n-butanol fraction of A. scholaris (NBF-ASME) was evaluated on rat aorta pre-contracted with phenyelphrine (PE, 1 µM). Aortic rings preparation were pre-incubated with various antagonists like 1H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ 10 μM), methylene blue (MB 10 μM), Nω-nitro-L-arginine methyl ester hydrochloride (l-NAME 10 μM), atropine (10 μM), indomethacin (1 μM), ML-9 and various K(+) channel blockers such as glibenclamide (10 μM) and tetraethyl ammonium (TEA 10 μM) for mechanism study.

RESULT

The results showed that pre-incubation of aortic rings with the extract (0.5, 1 and 2mg/mL) significantly inhibit the contractile response of the rings to phenylephrine-induced contraction (p<0.05-0.001). Removal of endothelium, incubation with L-NAME, indomethacin, atropine and propranolol did not significantly affect the relaxation effect of NBF-ASME. Furthermore, the K(+) channel blockers, TEA and glibenclamide showed no inhibitory effect. However, aortic rings pretreated with ODQ and ML-9 showed a significant suppression of the relaxation curve of NBF-ASME (p<0.01-0.001). In Ca(2+)-free solution, NBF-ASME inhibits the release of intracellular Ca(2+) from the sarcoplasmic reticulum. NBF-ASME also inhibits calcium chloride (CaCl2)-induced contraction in endothelium-denuded aortic rings.

CONCLUSION

The results from this study suggests that A. scholaris exerts vasodilation via calcium channels blockade, direct activation of soluble guanylate cyclase and possibly by also inhibiting the formation of inositol 1, 4, 5-triphosphate.

Modulatory potential of α-amyrin against hepatic oxidative stress through antioxidant status in Wistar albino rats

ETHNOPHARMACOLOGICAL RELEVANCE

α-Amyrin (a pentacyclic triterpene widely distributed in nature and isolated from a variety of plant sources and pharmacologically shown a wide spectrum of activity including anti-inflammatory, anti-ulcer, anti-hyperlipidemic, anti-tumor, and hepatoprotective actions) explored as hepatomodulator from the ethanol extract of the stem bark of Alstonia scholaris Linn. against CCl4-induced hepatic oxidative stress through antioxidant status in wistar albino rats.

MATERIALS AND METHODS

Experimental rats, hepato-oxidatively stressed by CCl4 (0.2 ml/kg b wt/twice a week, intra-peritoneally), were concurrently received α-amyrin (20mg/kg body weight/day, orally) for 30 consecutive days. Hepatomodulatory potential was assessed by using the serum- markers like γ-glutamyl transpeptidase (GGT), aspartate and alanine transaminases (AST, ALT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), acid phosphatase (ACP), sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GDH), and total bilirubin, total protein, glutathione reduced (GSH), ceruloplasmin, β-carotene, vitamin C and vitamin E in serum concomitantly with the hepatic-antioxidants like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-s-transferase (GST), and 5´-nucleotidase, acid ribonuclease, glucose-6-phosphatase, succinic dehydrogenase and cytochrome-P-450 in liver tissue whereas lipid peroxidation (LPO) was estimated in both serum and liver contents.

RESULTS

The assessment of all biochemical parameters registered a significant (P<0.001) hepatic oxidative stress in CCl4 treated rats, which was considerably recovered near to almost normal level in rats co-administered with α-amyrin at the dose level of 20mg/kg body weight/day for 30 consecutive days. The histoarchitectural examination of liver sections from treated groups further corroborated the hepatomodulatory potential of α-amyrin and compared with standard drug-silymarin.

CONCLUSIONS

These findings indicate that the modulatory potential of α-amyrin against hepatic oxidative stress possibly involve mechanism related to its ability to block the P-450 mediated CCl4 bioactivation through selective inhibitors of ROS (reactive oxygen species) as antioxidants brought about significant inhibition of the formation of LPO suggesting possible involvement of O2(●-), HO2, HO2(●-), H2O2 and •OH. Therefore this study suggests that the use of α-amyrin as a hepatomodulatory potent to feasibility for a promising liver curative drug.

beta-Amyrin and alpha-amyrin acetate isolated from the stem bark of Alstonia boonei display profound anti-inflammatory activity

CONTEXT

Alstonia boonei De Wild (Apocyanaceae) is used in ethnomedicine for the management of malaria, ulcer, rhematic pain, toothache, and inflammatory disorders.

OBJECTIVE

To investigate the anti-inflammatory potential of β-amyrin and α-amyrin acetate isolated from the stem bark of Alstonia boonei using animal models.

MATERIALS AND METHODS

Chromatographic purification of the crude methanol extract led to the isolation and structure elucidation of β-amyrin and α-amyrin acetate. Their anti-inflammatory activities were evaluated in rodents using egg albumen-induced paw edema and xylene-induced ear edema models. The gastric ulcerogenic, in vivo leucocyte migration, and RBC membrane stabilization tests were also investigated.

RESULTS

α-Amyrin acetate at 100 mg/kg showed significant (p < 0.05) inhibition of egg albumen-induced paw edema with % inhibition of 40 at the 5th hour. Oral administration up to 100 mg/kg did not produce significant (p > 0.01) irritation of the gastric mucosa while significant (p < 0.01) ulceration was recorded for indomethacin at 40 mg/kg compared with the negative control. At 100 μg/mL, both β-amyrin and α-amyrin acetate inhibited heat-induced hemolysis to as much 47.2 and 61.5%, respectively, while diclofenac sodium (100 μg/mL) evoked only 40.5% inhibition. Both compounds at 100 µg/ear produced significant (p < 0.01) inhibition of ear edema in mice by 39.4 and 55.5%, respectively. Also at 100 mg/kg (p.o.) α-amyrin acetate evoked 60.3% reduction in total leucocyte count and significant (p < 0.05) suppression (47.9%) of neutrophil infiltration.

DISCUSSION AND CONCLUSION

This study generally provided evidence of profound anti-inflammatory activity of β-amyrin and α-amyrin acetate isolated from the Alstonia boonei stem bark.

Therapeutic effects of various solvent fractions of Alstonia boonei (apocynaceae) stem bark on Plasmodium berghei-induced malaria

Malaria, the most important parasitic disease afflicting man is the leading cause of mortality and morbidity in the world. Chemotherapy remains the mainstay for the treatment and prevention of the disease in the absence of an effective vaccine. The incidence of resistance of malaria parasites to chemotherapy is increasing and complicated. This study was therefore undertaken in order to evaluate the therapeutic effects of fractions of the stem bark of A. boonei on P. berghei-induced malaria using chloroquine as control. Different doses (200 mg/kg and 400 mg/kg body weight) of methanolic extract (ME), n-hexane (HF), chloroform (CF), ethylacetate(EF) and aqueous (AF) fractions of the stem bark of A. boonei were administered orally to albino mice. Five milligrammes chloroquine base per kilogramme body weight (5 mg/kg bw) was used as positive control while the negative control mice received only the vehicle (5% v/v tween 80). The results obtained showed that the 400 mg/kg bw dose was more effective with respect to the parasite clearance than the 200 mg/kg bw dose. The 400 mg/kg bw dose of ME gave 68.1% percent parasite clearance. The CF gave the highest clearance of 98.4% at 400 mg/kg bw after 7 days treatment while chloroquine at 5 mg/kg bw gave 100% parasite clearance. The order of increasing potency of the fractions (parasite clearance) was (EF 50.0% < AF 60.3% < HF 63.1%, < CF 98.4%) indicating that the active principle in the stem bark was highest in the CF. Percentage parasitemia following exposure to these fractions also decreased in all groups in the same order and was only significant (p < 0.05) in CF (0.11%) compared to the untreated control group. The ME of A. boonei also caused increase in PCV by 15.5%. Purification enhanced PCV value as the HF and CF fractions gave 19.0% and 24.5% increases, respectively. However, 31.5% increase in PCV was obtained in the albino mice treated with chloroquine. The EF and AF gave increase of 10.0% and 11.0% increase relative to the negative control treated mice. The high bioactivity of CF and HF indicate that the putative compound(s) in A. boonei are lipophillic and further purification could enhance greater activity. Further work is required to isolate the bioactive compound for a promising antimalarial drug from the chloroform fraction.

Assessment of the antidiarrhoeal properties of the aqueous extract, the 80% methanol extract and its soluble fractions of the leaves of Alstonia congensis Engl. (Apocynaceae) in Wistar rats

AIM OF THE STUDY

To evaluate the antidiarrhoeal properties of Alstonia congensis leaves claimed to be effective for the treatment of diarrhoea by traditional healers during our ethnopharmacological investigation conducted in Kinshasa, Democratic Republic of Congo.

MATERIALS AND METHODS

The aqueous extract (decoction), and the 80% hot methanol extract (Soxhlet extraction) were obtained. This last extract was fractionated. The antidiarrhoeal activity was evaluated using castor oil and magnesium sulphate-induced diarrhoea in animals. The potential antibacterial activity of all samples was also assessed in vitro.

RESULTS

At all oral doses of 100 and 200 mg/kg body weight, all A. congensis samples showed significant and dose-dependent antidiarrhoeal activity in treated Wistar rats characterised by significant increase of onset time and decrease of all other diarrhoeal parameters at various degrees compared to untreated groups in both models. At the highest oral dose of 200 mg/kg bodyweight, the 80% hot methanol and aqueous extracts produced 79.8 ± 2.1% and 78.6 ± 0.5%, and 75.0 ± 2.1% and 71.4 ± 2.1% inhibition of defecation and diarrhoea respectively against castor oil-induced diarrhoea, and 75.0 ± 1.2% and 73.3±1.2% inhibition of diarrhoea respectively against magnesium sulphate-induced diarrhoea. The 80% hot methanol and aqueous detannified extracts showed low activity (42-47% inhibition of defecation and/or diarrhoea in both tests) suggesting that tannins may be responsible for the observed activity. At the same oral doses, the total alkaloid extract, the chloroform soluble fraction rich in alkaloids, the 80% methanol and the alkaline aqueous soluble subfractions produced more than 50% inhibition of defecation and/or diarrhoea in both tests. From the antibacterial testing in vitro, results indicated that all A. congensis samples exhibited an antibacterial activity mainly against bacteria implicated in diarrhoea with MIC and MBC values in the range of 15.6-500 μg/ml. The most active samples were the aqueous (decoction) and the 80% hot methanol dried extracts, the chloroform subfraction rich in alkaloids and the total alkaloid extract (MIC: 15.7-125 μg/ml, MBC: 31.2-250 μg/ml). Proteus varibilis was found to be the most resistant microorganism.

CONCLUSION

These reported results can partly support and justify the traditional use of extracts from Alstonia congensis leaves for the treatment of diarrhoea in tradittional medicine.

Evaluation of anticancer activity of the alkaloid fraction of Alstonia scholaris (Sapthaparna) in vitro and in vivo

The anticancer effect of various doses of an alkaloid fraction of Sapthaparna, Alstonia scholaris (ASERS), was studied in vitro in cultured human neoplastic cell lines (HeLa, HepG(2), HL60, KB and MCF-7) and in Ehrlich ascites carcinoma bearing mice. Treatment of HeLa cells with 25 microg/mL ASERS resulted in a time dependent increase in the antineoplastic activity and the greatest activity was observed when the cells were exposed to ASERS for 24 h. However, exposure of cells to ASERS for 4 h resulted in 25% viable cells and hence this time interval was considered to be the optimum time for treatment and further studies were carried out using this time. Treatment of various cells with ASERS resulted in a concentration dependent decline in the viable cells and a nadir was reached at 200 microg/mL in all the cell lines studied. The IC50 was found to be 5.53, 25, 11.16, 10 and 29.76 microg/mL for HeLa, HePG2, HL60, KB and MCF-7 cells, respectively. Similarly, administration of ASERS, once daily for 9 consecutive days to the tumor bearing mice caused a dose dependent remission of the tumor up to 240 mg/kg body weight, where the greatest antitumor effect was observed. Since 240 mg/kg ASERS showed toxic manifestations, the next lower dose of 210 mg/kg was considered as the best effective dose, in which 20% of the animals survived up to 120 days post-tumor-cell inoculation as against no survivors in the saline treated control group. The ASERS treatment resulted in a dose dependent elevation in the median survival time (MST) and the average survival time (AST) up to 240 mg/kg ASERS and declined thereafter. The surviving animals were healthy and disease free. The effect of ASERS was better than cyclophosphamide, which was used as a positive control, where all the animals succumbed to death by 40 days and the MST and AST were 19.5 and 18.3 days, respectively. The effective dose of 210 mg of ASERS was 3/10 of the LD50 dose, which increased the MST and AST up to 54 and 49.5 days, respectively.

Antipyretic activity of Alstonia macrophylla Wall ex A. DC: an ethnomedicine of Andaman Islands

PURPOSE

Alstonia macrophylla Wall ex A. DC. Leaf, used in different ailments by the Onge tribes of Little Andaman Island, India, was investigated for its antipyretic potential.

METHODS

The methanol extract and its fractions were tested on normal body temperature and yeast-induced pyrexia in Wistar Albino rats.

RESULTS

The leaf extract at oral doses of 200 and 300 mg/kg, and the n-butanol fractions of the extract at 50 mg/kg showed significant reduction in normal body temperature and yeast-provoked elevated temperature in a dose-dependent manner comparable to that of standard antipyretic drug paracetamol. The antipyretic effect was started at 1 h and extended for at least 5 h after the drug administration.

CONCLUSIONS

The antipyretic effect was more pronounced when the fraction A and B was administered together, indicating that both the fractions may contain antipyretic compounds which produce an additive effect in combination. Phytochemically these fractions contain beta-sitosterol and ursolic acid.

Evaluation of Alstonia scholaris leaves for broncho-vasodilatory activity

The present study demonstrates that the ethanol extract of Alstonia scholaris (Apocynaceae) leaves induced pronounced bronchodilatory activity in anaesthetized rats with the probable involvement of prostaglandins. However, in vitro preparations of guinea-pig trachea did not confirm this property, indicating that bronchodilation is not due to the direct tracheal smooth muscle relaxation. The vasodilatory activity of the extract was independent of adrenergic or muscarinic receptors or prostaglandins but was mainly via endothelial-derived relaxing factor, nitric oxide. The extract inhibited the spontaneous movements of rabbit jejunum and contractile effects of acetylcholine and histamine on guinea-pig ileum. Additionally, the extract caused marked reduction of barium chloride-, potassium chloride- and calcium chloride-induced contraction on guinea-pig ileum and pulmonary artery, implying a direct interference of plant extract with the influx of calcium ions into cells. However, the extract has no detectable effect on mobilization of intracellular calcium. These results coupled with the in vivo effects of ethanol extract reveal that the Alstonia scholaris leaves possess broncho-vasodilatory activity mediated presumably by prostaglandins, calcium antagonism and endothelium-derived relaxing factor(s).

The effect of seasonal variation on the antineoplastic activity of Alstonia scholaris R. Br. in HeLa cells

In order to evaluate the seasonal variation as well as cytotoxicity of different fractions of Alstonia scholaris R. Br. (ASE), the HeLa cells were treated with different doses of various fractions of ASE collected in monsoon, winter and summer. The exposure of HeLa cells to different extracts prepared from the stem bark collected in monsoon, winter and summer seasons resulted in a dose dependent increase in the cell killing effect of ASE and the highest cell killing effect was observed for the extract prepared from the summer collections. Similarly, treatment of HeLa cells with different doses of various fractions of the Alstonia scholaris extract viz. residue (ASERS), steroidal (ASEST), chloroform (ASECH), petroleum ether (ASEPE), diethyl ether (ASEDE), ethyl acetate (ASEEA), n-butanol (ASENB), aqueous (ASEAQ) and echitamine chloride (ECL) also resulted in a dose dependent decline in the cell viability, where the greatest cytotoxic effect was observed for residue (ASERS), followed by the whole extract (ASE) and chloroform (ASECH) fraction, while the least activity was observed for the steroidal (ASEST) fraction. The cytotoxicity declined ASERS > ASE > ASECH >ECL > ASEEA > ASEDE > ASEPE > ASENB > ASEAQ > ASEST in order. Our study demonstrates that the extract prepared from the summer collection, and the fractions containing the alkaloids were highly effective in cell killing. The extract of ASE was more powerful than the active principle echitamine present in ASE.

CNS activity of Alstonia macrophylla leaf extracts: an ethnomedicine of Onge of Bay Islands

Methanol extract at 100-200 mg/kg p.o. and major nonpolar fraction B at 50 mg/kg of Alstonia macrophylla leaves caused a significant reduction in spontaneous activity, remarkable decrease in exploratory behavioural pattern, a reduction in muscle relaxant activity and also significantly potentiated phenobarbitone sodium-induced sleeping time. The phytochemical study of crude leaf extract revealed the presence of tannin, triterpenoid, flavonoid, sterol, alkaloid and reducing sugars. Further fractionation and purification of the n-butanol part of methanol extract yielded fraction A, fraction B and fraction C along with some minor fatty acids as the major compounds.

Treatment with Alstonia scholaris Enhances Radiosensitivity In vitro and In vivo

The radiosensitizing effect of 5 micrograms/mL of alkaloid fraction of Alstonia scholaris (ASERS) was evaluated in various neoplastic cell lines, namely: HeLa, HePG2, HL60, MCF-7, and KB exposed to 0, 0.5, 1, 2, 3, and 4 Gy of gamma-radiation. The irradiation of various cells caused a dose-dependent elevation in the cytotoxicity, and a maximum cytotoxic effect was observed at 4 Gy (the highest dose) in all the cell lines studied. The ASERS pretreatment increased the effect of radiation as evidenced by enhanced cell killing when compared with the concurrent phosphate-buffered saline (PBS) treated irradiation group. The greatest elevation in cell killing was observed for HeLa and KB cells, followed by HL60, MCF7, and HePG2 cells. The in vitro observations were confirmed by in vivo studies, where the Ehrlich ascites carcinoma (EAC) bearing mice were treated with 120 mg/kg body weight of ASERS before exposure to 0, 1, 2, 4, 6, and 8 Gy of hemibody (below the rib cage) gamma-radiation. Irradiation of EAC mice caused a dose-dependent tumor regression, as evidenced by increased life span of the animals. The pretreatment of tumor-bearing animals with 120 mg/kg ASERS resulted in a further remission in the tumor when compared with the concurrent nondrug-treated irradiated controls; as a result there was a radiation dose-dependent increase in the life span of tumor-bearing animals receiving 120 mg/kg ASERS, except for 8 Gy, where it was less than the concurrent control. The above findings corroborate with a time-dependent decrease in the glutathione (GSH) contents, accompanied by an increase in lipid peroxidation. Our study demonstrates that ASERS treatment enhances the effect of radiation and results in disease-free survival of the mice.

Antibacterial activity of Alstonia scholaris and Leea tetramera

The crude methanolic extracts of the leaves, stem and root barks of Alstonia scholaris and Leea tetramera on partitioning (petrol, dichloromethane, ethyl acetate, butanol) gave fractions exhibiting improved and broader spectrum of antibacterial activity. Especially the butanol fractions of A. scholaris and the root bark of L. tetramera. None of the fractions were active against the fungi tested.

Evaluation of anti-inflammatory activity of Alstonia macrophylla Wall ex A. DC. leaf extract

Methanolic extract of dried leaves of Alstonia macrophylla Wall ex A. DC. and its fractions were investigated for its anti-inflammatory activity. The extract at a concentration of 200 mg kg(-1) and 400 mg kg(-1), p.o. and its fractions at 25 mg kg(-1) and 50 mg kg(-1), p.o. showed the significant dose dependent antiinflammatory activity in carrageenan and dextran-induced rats hind paw edema (acute models) as well as in cotton pellet-induced granuloma (chronic model) in rats. Anti-inflammatory activity of the tested extract and its fractions was comparable with that of the standard drug Indomethacin (10 mg kg(-1)).

Effect of Alstonia scholaris bark extract on testicular function of Wistar rats

AIM

To evaluate the antifertility effect of Alstonia scholaris bark extract in male rats.

METHODS

In male Wistar rats Alstonia scholaris bark extract was given by oral route at a dose of 200 mg/day for 60 days. The fertility and testicular function were assessed by mating tests, sperm motility, sperm concentration, biochemical indices and testicular cell population dynamics.

RESULTS

Oral feeding with the extract at a dose of 200 mg/day for the period of 60 days did not cause body weight loss, while the weights of testes, epididymides, seminal vesicle and ventral prostate were significantly reduced. The production of step-19 spermatids was reduced by 79.6% in treated rats. The population of preleptotene and pachytene spermatocytes were decreased by 61.9% and 60.1%, respectively. Spermatogonia and Sertoli cell population were also affected. The seminiferous tubule and Leydig cell nuclear area were reduced significantly (P<0.01) when compared to the controls. Reduced sperm count and motility resulted in a total suppression of fertility. A significant fall in the protein and sialic acid content of the testes, epididymides, seminal vesicle and ventral prostate as well as glycogen content of testes were also noticed. The fructose content in the seminal vesicle was lowered whereas the testicular cholesterol was elevated as compared with the controls. The following compounds were obtained from the extract with chromatographic separation over Si-gel column: agr-amyrin, bgr-amyrin, lupiol acetate, venenative, rhazine and yohimbine.

CONCLUSION

At the dose level employed, Alstonia scholaris bark extract has a significant antifertility effect in male rats; the primary site of action may be post meiotic germ cells (Step 19 spermatids).