Evaluating Water bitter leaf (Struchium sparganophora) and Scent Leaf (Ocimum gratissimum) extracts as sources of nutraceuticals against manganese-induced toxicity in fruit fly model

Tropical vegetables remain one of the major sources of functional foods and nutraceuticals, while their constituent phytochemicals, especially alkaloids, have been reported to exhibit neuroprotective properties. Here, the protective effect of alkaloid extracts from Scent leaf (Ocimum gratissimum) and Water bitter leaf (Struchium sparganophora) on manganese (Mn)- induced toxicity in wild type fruit fly (Drosophila melanogaster) model was investigated. Flies were exposed to 30 mM of Mn, the alkaloid extracts (20 and 200 µg/g) and co-treatment of Mn plus extracts, respectively. The survival rate and locomotor performance of the flies were assessed 7 days post-treatment, after which the flies were homogenized and assayed for activities of acetylcholinesterase (AChE), monoamine oxidase (MAO), glutathione-S transferase (GST), catalase, superoxide dismutase SOD), as well as total thiol, reactive oxygen species (ROS) and neural L-DOPA levels. Results showed that the extract significantly reversed Mn-induced reduction in the survival rate and locomotor performance of the flies. Furthermore, both extracts counteracted the Mn-induced elevation in AChE and MAO activities, as well as reduced antioxidant enzyme activities, with a concomitant mitigation of Mn-induced elevated ROS and neural L-DOPA level. The HPLC characterization of the extracts revealed the presence of N-propylamine, Vernomine and Piperidine as predominant in Water bitter leaf extract, while 2, 6-dimethylpyrazine and sesbanimide were found in scent leaf extract. Therefore, the alkaloid extract of these leaves may thus be sources of useful nutraceuticals for the management of pathological conditions associated with manganese toxicity.

Chaya (Jatropha tanjorensis) leafs protect against sodium benzoate mediated renal dysfunction and hepatic damage in rats

Background

Jatropha tanjorensis is a commonly consumed green leafy plant that has found usage in folk medicine. Sodium benzoate (C6H5COONa) is a widely used preservative in food/drink industries with potential cytotoxicity. Protective effect of some leafy plants on xenobiotic-induced toxicity have been established. Hence, this study sought to investigate the protective effect of methanolic leaf extract of Jatropha tanjorensis on sodium benzoate mediated renal and hepatic dysfunction in rats.

Results

Sodium benzoate treatment caused significant (P < 0.05) alteration in kidney (serum urea, uric acid, and creatinine) and liver (aspartate and alanine transaminases, acid and alkaline phosphatases) damage markers, serum albumin, globulin and total protein levels as well as cellular architecture which were significantly reversed in groups treated with the leaf extracts. Phytochemical screening of the leaf extract revealed the presence of terpenoids, saponins, cardiac glycosides, flavonoids and tannins.

Conclusion

Sodium benzoate-induced alterations in the renal and hepatic indices were mitigated following treatment with J. tanjorensis leaf extracts which suggests protective effect of the extract against sodium benzoate intoxication.

Influence of gallic and tannic acid on therapeutic properties of acarbose in vitro and in vivo in Drosophila melanogaster

Background

In this study, gallic acid (GA) and its polymeric form-tannic acid (TA) which are two phenolic acids found abundantly distributed in plant food sources were investigated for their influence on therapeutic properties of acarbose (AC) in vitro and in vivo in Drosophila melanogaster.

Methods

Combinations of AC and GA or TA were assessed for their alpha-glucosidase and alpha-amylase inhibitory effects as markers of anti-hyperglycemic properties, as well as their free radicals scavenging, Fe²⁺ chelating and malondialdehyde (MDA) inhibitory effects (in vitro). Furthermore, wild type D. melanogaster cultures were raised on diets containing AC, GA, TA and their various combinations for seven days. Thereafter, flies were homogenized and glucose concentrations, alpha-glucosidase and alpha-amylase activities, as well as reactive oxygen species (ROS) and total thiol levels were determined.

Results

The results showed that GA and TA up to 5 mg/ml significantly (p < 0.05) increased the enzymes' inhibitory effects and antioxidant properties of AC in vitro. Also, there was significant reduction in glucose concentration, enzyme activities and ROS level in D. melanogaster fed diets supplemented with phenolic acids and acarbose.

Conclusions

These bioactive compounds–drug interactions provide useful information on improving the therapeutic properties of acarbose especially in its use as an antidiabetic drug.

Dietary supplementation of jute leaf (Corchorus olitorius) modulates hepatic delta-aminolevulinic acid dehydratase (δ-ALAD) activity and oxidative status in high-fat fed/low streptozotocin-induced diabetic rats

Impaired liver function is associated with decreased hepatic delta-aminolevulinic acid dehydratase (δ-ALAD) activity in diabetes mellitus. Hence, this study described the effect of dietary jute leaf (Corchorus olitorius) on hepatic δ-ALAD activity in high-fat fed combined with low-dose streptozotocin administered diabetic rats. Animals were fed diets containing 35% fat for 14 days prior to a single administration of low-dose (35 mg/kg body weight) streptozotocin to induce diabetes. Thereafter, the animals were randomly placed in groups and fed 100 mg/g jute leaf-supplemented diets for 30 days. The result showed that jute leaf supplementation significantly (p < 0.05) reversed the decreased hepatic δ-ALAD activity, increased hepatic catalase and SOD activity accompanying the decrease in serum AST and AST activities. This finding suggests that restoration of hepatic δ-ALAD activity, modulation of hepatic function biomarkers, and increase in antioxidant status could be possible underlying events mediating the hepatoprotective effect of jute leaf in diabetic conditions. PRACTICAL APPLICATIONS: Decrease in hepatic δ-ALAD activity has been associated with diabetes-induced hepatotoxicity arising from prolonged and uncontrolled hyperglycemia. Therefore, increased δ-ALAD activity represents improved hepatic function in diabetic situations. Antidiabetic properties of jute leaf have been demonstrated but information on its effect on hepatic δ-ALAD is lacking. Thus, this study revealed that dietary supplementation of jute leaf restored hepatic δ-ALAD activities and improved liver antioxidant status in diabetic rats which is an indication of its hepatoprotective properties.

Cardio-protective and antioxidant properties of caffeic acid and chlorogenic acid: Mechanistic role of angiotensin converting enzyme, cholinesterase and arginase activities in cyclosporine induced hypertensive rats

Caffeic acid (CAA) and chlorogenic acid (CHA) are important members of hydroxycinnamic acid with natural antioxidant and cardio-protective properties. The present study aimed to determine the effect of CAA and CHA on systolic blood pressure, heart rates (HR) as well as on the activity of the angiotensin-1-converting enzyme (ACE), acetylcholinesterase (AChE), butrylcholinesterase (BChE) and arginase in cyclosporine-induced hypertensive rats. Experimental rats were distributed into 7 groups (n = 6): normotensive control rats; hypertensive rats (induced rats) as well as hypertensive- treated groups with captopril (10 mg/kg/day), CAA (10 and 15 mg/kg/day) and CHA (10 and 15 mg/kg/day), respectively. The experiment lasted for 7 days and the systolic blood pressure (SBP) and heart rates were recorded using tail-cuff method. Oral administration of captopril, caffeic acid and chlorogenic acid normalized hypertensive effect caused by cyclosporine administration. CAA and CHA significantly (P < 0.05) reduced SBP and HR, activity of ACE, AChE, BChE and arginase in the treated hypertensive rats compared with cyclosporine induced-hypertensive rats. Likewise, CAA and CHA improved nitric oxide (NO) bioavailability, increased catalase activity and reduced glutathione content while malondialdehyde (MDA) level was reduced compared with cyclosporine hypertensive rats. Findings from this study shows that CAA and CHA exhibited blood pressure lowering properties and reduced activities of key enzymes linked to the pathogenesis of hypertension in cyclosporine-induced rats. These might be some of the possible mechanisms of action by which their cardio-protective properties are exhibited.

Antiulcer Agents: From Plant Extracts to Phytochemicals in Healing Promotion

In this narrative review, we have comprehensively reviewed the plant sources used as antiulcer agents. From traditional uses as herbal remedies, we have moved on to preclinical evidence, critically discussing the in vitro and in vivo studies focusing on plant extracts and even isolated phytochemicals with antiulcerogenic potential. A particular emphasis was also paid to Helicobacter pylori activity, with emphasis on involved mechanisms of action. Lastly, the issue of safety profile of these plant products has also been addressed.

Modulation of some markers of erectile dysfunction and malonaldehyde levels in isolated rat penile tissue with unripe and ripe plantain peels: identification of the constituents of the plants using HPLC

CONTEXT

Plantain fruit pulp has been used as a natural remedy to manage erectile dysfunction (ED) in traditional medicine. However, the potency of the peel has not been examined with respect to ED management.

OBJECTIVE

This study investigated and compared the inhibitory potential of unripe (UPP) and ripe (RPP) plantain peels on some enzymes associated with ED and Fe²⁺-induced oxidative stress in albino rat penile homogenate in vitro.

MATERIALS AND METHOD

Aqueous extract of the peels was prepared and the effect on phosphodiesterase-5 (PDE-5), arginase, acetylcholinesterase (AChE), angiotensin-I converting enzyme (ACE) and Fe²⁺-induced malonyladehyde in isolated albino rat penile homogenate were investigated. Phenolic constituents of the peels powder were characterized using high-performance liquid chromatography coupled with diode array detector (HPLC-DAD).

RESULT

Extract from UPP had higher PDE-5 (IC₅₀ = 3.10 μg/mL), arginase (IC₅₀ = 0.96 μg/mL), AChE (IC₅₀ = 6.30 μg/mL) and ACE (IC₅₀ = 0.41 μg/mL) inhibitory ability compared with RPP (PDE-5, IC₅₀ = 4.33 μg/mL; arginase, IC₅₀ = 1.34 μg/mL; AChE, IC₅₀ = 8.64 μg/mL; ACE, IC₅₀ = 0.63 μg/mL). The extract from UPP also had higher inhibition of Fe²⁺-induced lipid peroxidation. HPLC-DAD analysis revealed that gallic and caffeic acids, rutin, quercitrin and quercetin were abundant in UPP, while catechin, kaempferol, chlorogenic and ellagic acids were the dominant phenolic compounds in RPP.

DISCUSSION AND CONCLUSION

Inhibition of enzymes associated with ED and lipid peroxidation could be linked with the phenolic compounds. However, UPP appeared to be more potent.

Polyphenolic compositions and in vitro angiotensin-I-converting enzyme inhibitory properties of common green leafy vegetables: A comparative study

This study compared the phenolic compositions of common green leafy vegetable extracts from Vernonia amygdalina (VA), Telfairia occidentalis (TO), Talinium triangulare (TT), and Amaranthus hybridus (AH) and their effects on the angiotensin-I-converting enzyme (ACE) and cisplatin-induced malonylaldehyde (MDA) production in an isolated rat kidney homogenate. HPLC confirmed the presence of phenolic compounds in the extracts. Furthermore, all extracts inhibited ACE activity dosedependently; however, the extract from VA exhibited the highest ACE activity while TT exhibited the least. Incubation of the kidney homogenate with 1mM cisplatin caused an increase in MDA production; however, all the extracts inhibited the level of MDA produced. Nevertheless, VA extract exhibited the highest inhibition. These activities of the vegetable extracts could be attributed to their phenolic compositions and may suggest some possible mechanism of the actions. However, VA appeared to be the most potent among the vegetables tested.

Drying Methods Alter Angiotensin-I Converting Enzyme Inhibitory Activity, Antioxidant Properties, and Phenolic Constituents of African Mistletoe (Loranthus bengwensis L) Leaves

This study investigated the most appropriate drying method (sun drying, oven drying, or air drying) for mistletoe leaves obtained from almond tree. The phenolic constituents were characterized using high-performance liquid chromatography–diode array detector, while the inhibitory effect of the aqueous extracts of the leaves on angiotensin-I converting enzyme (ACE) was determined in vitro as also the antioxidant properties. Oven-dried extract (kidney [276.09 μg/mL] and lungs [303.41 μg/mL]) had the highest inhibitory effect on ACE, while air-dried mistletoe extract (kidney [304.47 μg/mL] and lungs [438.72 μg/mL]) had the least. Furthermore, the extracts dose-dependently inhibited Fe2+ and sodium nitroprusside-induced lipid peroxidation in rat’s heart and kidney. Also, all extracts exhibited antioxidative properties as typified by their radical scavenging and Fe-chelating ability. Findings from this study revealed that oven drying is the best of the 3 drying methods used for mistletoe obtained from almond host tree, thus confirming that diversity in drying methods leads to variation in phenolic constituents and biological activity of plants.

Effect of Two Ginger Varieties on Arginase Activity in Hypercholesterolemic Rats

Recently, ginger has been used in traditional Chinese medicine as an herbal therapy for treating several cardiovascular diseases, however, information on its mechanism of action is limited. The present study assessed the effect of two ginger varieties (Zingiber officinale and Curcuma longa) on the arginase activity, atherogenic index, levels of liver thiobarbituric acid reactive substances (TBARSs), and plasma lipids in rats fed with a high-cholesterol (2%) diet for 14 days. Following the treatment period, it was found that feeding a high-cholesterol diet to rats caused significant (p < 0.05) increases in arginase activity, atherogenic index, levels of TBARS, total cholesterol (TC), triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C) with a concomitant decrease in high-density lipoprotein cholesterol (HDL-C). However, both ginger and turmeric (2% and 4%) caused significant (p < 0.05) decreases in arginase activity and the atherogenic index, and prevented hypercholesterolemia by decreasing the TC, TGs, and LDL-C while increasing the HDL-C when compared with the controls. In conclusion, dietary supplementation with both types of rhizomes (ginger and turmeric) inhibited arginase activity and prevented hypercholesterolemia in rats that received a high-cholesterol diet. Therefore, these activities of ginger and turmeric represent possible mechanisms underlying its use in herbal medicine to treat several cardiovascular diseases.

Polyphenolic Composition and Evaluation of Antioxidant Activity, Osmotic Fragility and Cytotoxic Effects of Raphiodon echinus (Nees &amp; Mart.) Schauer

Raphiodon echinus (R. echinus) is used in Brazilian folk medicine for the treatment of inflammation, coughs, and infectious diseases. However, no information is available on the potential antioxidant, cytotoxicity and genotoxicity of this plant. In this study, the polyphenolic constituents, antioxidant capacity and potential toxic effects of aqueous and ethanolic extracts of R. echinus on human erythrocytes and leukocytes were investigated for the first time. R. echinus extracts showed the presence of Gallic, chlorogenic, caffeic and ellagic acids, rutin, quercitrin and quercetin. Aqueous and ethanolic extracts of R. echinus exhibited antioxidant activity in DPPH radical scavenging with IC50 = 111.9 μg/mL (EtOH extract) and IC50 = 227.9 μg/mL (aqueous extract). The extracts inhibited Fe(2+) (10 μM) induced thiobarbituric acid reactive substances (TBARS) formation in rat brain and liver homogenates. The extracts (30-480 μg/mL) did not induce genotoxicity, cytotoxicity or osmotic fragility in human blood cells. The findings of this present study therefore suggest that the therapeutic effect of R. echinus may be, in part, related to its antioxidant potential. Nevertheless, further in vitro and in vivo studies are required to ascertain the safety margin of its use in folk medicine.

Phenolic compounds from sandpaper (ficus exasperata) leaf inhibits angiotensin 1 converting enzyme in high cholesterol diet fed rats

ETHNOPHARMACOLOGICAL RELEVANCE

Sandpaper [Ficus exasperata Vahl (Moraceae)] leaf has been reportedly used in folklore for the management/treatment of cardiovascular diseases with little/or no scientific basis for their action. This study sought to investigate the effect of dietary supplementation of sandpaper leaf on angiotensin-I converting enzyme (ACE) activity in hypercholesterolemia as well as the effect of their phenolic extract on this enzyme in vitro.

MATERIALS AND METHODS

The phenolic extract was prepared, then, the inhibitory effect of the leaf extract on ACE was determined in vitro. Thereafter, the effect of dietary supplementation of sandpaper leaf on angiotensin-I converting enzyme (ACE) activity in high cholesterol diet fed rats for 14 days was evaluated as well as some biochemical parameters.

RESULTS

The result revealed that under in vitro condition, the phenolic extract inhibited ACE (IC50=14.7µg/mL) in a dose-dependent manner (0-10µg/mL). Feeding high cholesterol diets to rats caused a significant (P<0.05) increase in the ACE activity. However, there was a significant (P<0.05) decrease in the ACE activity as a result of supplementation with the sand paper leaves. Furthermore, there was a significant (P<0.05) increase in the plasma lipid profile with a concomitant increase in malondialdehyde (MDA) content in rat liver and heart tissues. However, supplementing the diet with sandpaper leaf (either 10% or 20%) caused a significant (P<0.05) decrease in the plasma total cholesterol (TC), triglyceride (TG), very low density lipoprotein-cholesterol (VLDL-C), and low-density lipoprotein-cholesterol levels (LDL-C), and in MDA content in the tissues. Conversely, supplementation caused a significant (P<0.05) increase in plasma high-density lipoprotein-cholesterol level when compared with the control diet. Reversed phase HPLC analysis of the extract revealed Quercitrin (43.7mg/g), chlorogenic acid (42.8mg/g) and caffeic acid (33.9mg/g) as the major phenolics in the leaf.

CONCLUSION

The inhibition of ACE activity and prevention of hypercholesterolemia by sandpaper leaf could be part of the possible mechanism underlying its anti-hypertensive property which could lay credence to its use in folk medicine. However, these activities may be directly/indirectly attributed to the polyphenolics present.

Inhibition of angiotensin-1-converting enzyme activity by two varieties of ginger (Zingiber officinale) in rats fed a high cholesterol diet

Angiotensin-1-converting enzyme (ACE) inhibitors are widely used in the treatment of cardiovascular diseases. This study sought to investigate the inhibitory effect of two varieties of ginger (Zingiber officinale) commonly consumed in Nigeria on ACE activity in rats fed a high cholesterol diet. The inhibition of ACE activity of two varieties of ginger (Z. officinale) was investigated in a high cholesterol (2%) diet fed to rats for 3 days. Feeding high cholesterol diets to rats caused a significant (P<.05) increase in the ACE activity. However, there was a significant (P<.05) inhibition of ACE activity as a result of supplementation with the ginger varieties. Rats that were fed 4% white ginger had the greatest inhibitory effect as compared with a control diet. Furthermore, there was a significant (P<.05) increase in the plasma lipid profile with a concomitant increase in malondialdehyde (MDA) content in rat liver and heart tissues. However, supplementing the diet with red and white ginger (either 2% or 4%) caused a significant (P<.05) decrease in the plasma total cholesterol, triglyceride, very low density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol levels, and in MDA content in the tissues. Conversely, supplementation caused a significant (P<.05) increase in plasma high-density lipoprotein-cholesterol level when compared with the control diet. Nevertheless, rats fed 4% red ginger had the greatest reduction as compared with control diet. In conclusion, both ginger varieties exhibited anti-hypercholesterolemic properties in a high cholesterol diet fed to rats. This activity of the gingers may be attributed to its ACE inhibitory activity. However, white ginger inhibited ACE better in a high cholesterol diet fed to rats than red ginger. Therefore, both gingers could serve as good functional foods/nutraceuticals in the management/treatment of hypertension and other cardiovascular diseases.

Inhibition of α-amylase and α-glucosidase activities by ethanolic extract of Telfairia occidentalis (fluted pumpkin) leaf

OBJECTIVE

To investigate the inhibitory effect of Telfairia occidentalis Hook f. (Curcubitaceae) (T. occidentalis) leaf on key enzyme linked to type-2 diabetes (α - amylase and α - glucosidase) as well as assess the effect of blanching (a commonly practiced food processing technique) of the vegetable on these key enzymes.

METHODS

Fresh leaves of T. occidentalis were blanched in hot water for 10 minutes, and the extracts of both the fresh and blanched vegetables were prepared and used for subsequent analysis. The inhibitory effect of the extract on α - amylase and α - glucosidase activities as well as some antioxidant parameter was determined in vitro.

RESULTS

The result revealed that unprocessed T. occidentalis leaf reduce Fe(3+) to Fe(2+) and also inhibited α - amylase and α - glucosidase activities in a dose dependent manner. However, blanching of the leafy vegetables caused a significant (P<0.05) increase in the antioxidant properties but decrease their ability to inhibit α - amylase and α - glucosidase activities.

CONCLUSIONS

This antioxidant properties and enzyme inhibition could be part of the mechanism by which they are used in the treatment/prevention of type-2 diabetes. However, the blanched vegetable reduces their ability to inhibit both α - amylase and α - glucosidase activity in vitro.

Antioxidant properties and inhibitory effect of ethanolic extract of Struchium sparganophora (Ewuro Odo) leaf on α--amylase and α--glucosidase activities

Recent studies have shown that vegetables consumption could lower the risk of diabetes mellitus. Therefore, this study sought to investigate the inhibitory effect of Struchium sparganophora (Ewuro Odo) leaf on key enzyme linked to type-2 diabetes (α-amylase and α-glucosidase) as well as assessing the effect of blanching (a commonly practiced food processing technique) of this leafy vegetable on these key enzymes. Fresh leaves of Struchium sparganophora were blanched in hot water for 10 minutes, and the 70% ethanolic extracts of the fresh and blanched vegetables were prepared and used for subsequent analysis. The antioxidant properties and interaction of the extracts on α - amylase and α - glucosidase activities was determined in vitro. The result revealed that Struchium sparganophora leaf scavenged DPPH free radical and also inhibited α -amylase and α - glucosidase activities in a dose dependent manner (0.05 -0.2 mg/ml). However, blanching of this leafy vegetables caused a significant (P<0.05) increase in the antioxidant properties as typified by the DPPH radical scavenging ability and reducing property but decrease their ability to inhibit α - amylase and α - glucosidase activities. This antioxidant properties and enzyme inhibition could be part of the mechanism by which green leafy vegetables exert their anti-diabetic properties. However, blanching of the vegetable could reduce their ability to inhibit both α - amylase and α - glucosidase activity, but enhance their antioxidant properties in vitro.

Inhibitory effect of some tropical green leafy vegetables on key enzymes linked to Alzheimer's disease and some pro-oxidant induced lipid peroxidation in rats' brain

This study sought to investigate the inhibitory effect of some commonly consumed Nigerian green leafy vegetables (raw and blanched) on acetylcholinesterase and butyrylcholinesterase (key enzyme linked to Alzheimer's disease) activities and some pro-oxidants (FeSO4, Sodium nitroprusside and Quinolinic acid) induced lipid peroxidation in rat brain in vitro. Three commonly consumed green leafy vegetables in Nigeria [Amarantus cruentus (Arowojeja), Struchium sparganophora (Ewuro-odo) and Telfairia occidentalis (Ugwu] were blanched in hot water for 10 min, and the extracts of the raw and blanched vegetables were prepared and used for subsequent analysis. The result revealed that all the vegetables inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity as well as the pro-oxidants induced lipid peroxidation in rat brain in a dose dependent manner; however, Amarantus cruentus extract (EC50 = 97.9 μg/ml) had the highest inhibitory effect on acetylcholinesterase activity while Telfairia occidentalis extract (EC50 = 52.7 μg/ml) had the highest inhibitory effect on butyrylcholinesterase activity. However, blanching of the vegetables caused a significant (P < 0.05) decrease in the inhibitory effect of the vegetables on AChE activities while it enhanced the inhibition of the pro-oxidants induced lipid peroxidation in rat brain in vitro. Therefore, some of the possible mechanism by which green leafy vegetables exert their neuroprotective activities could be through the inhibition of acetylcholinesterase and butyrylcholinesterase activities and prevention of lipid peroxidation in the brain. However, blanching of the vegetables could reduce their ability to inhibit acetylcholinesterase and butyrylcholinesterase activity.