In vitro antioxidant activity and effect of Parkia biglobosa bark extract on mitochondrial redox status

Parkia biglobosa Jacq. (Locust Bean) leaves and seeds extracts attenuates diabetic-linked cognitive dysfunction in streptozotocin-induced male wistar rats

Diabetes Mellitus is a metabolic disorder characterized by high blood glucose levels, causing significant morbidity and mortality rates. This study investigated the antidiabetic, neuroprotective, and antioxidant effects of ethanol extracts of Parkia biglobosa (PB) leaves and seeds in streptozotocin (STZ)-induced diabetic rats. The administration of STZ significantly elevated fasting blood glucose levels (FBGL) to 355-400 mg/mL compared to 111 mg/mL in normal controls, indicating hyperglycemia. Treatment with PB extracts at 100 mg/kg and 200 mg/kg significantly (p < 0.05) reduced FBGL in a dose-dependent manner. No significant difference was observed between the effects of metformin and PB extracts at 200 mg/kg. Cognitive dysfunction, assessed using the Y-maze test, was significantly improved in groups treated with PB extracts (p < 0.05), particularly at 200 mg/kg, through inhibition of cholinesterase activity and protection against oxidative damage. Both PB extracts also demonstrated significant inhibition (p < 0.05) of α-amylase and α-glucosidase activity, reducing postprandial hyperglycemia, with a stronger inhibition at 200 mg/kg. Additionally, PB extracts significantly increased catalase (CAT) and superoxide dismutase (SOD) activities, reversing the diabetes-induced decline in antioxidant enzyme levels. Monoamine oxidase (MAO) activity, elevated in diabetic conditions, was significantly downregulated by PB treatment, further contributing to neuroprotection. The neuroprotective effects may be attributed to the inhibition of cholinesterase and MAO, which help maintain neurotransmitter levels, alongside the antioxidant properties that mitigate oxidative stress in the brain. These findings suggest that PB extracts could serve as a natural therapeutic agent for diabetes management, with its effects comparable to metformin at higher doses.

Gallic acid modulates purine metabolism and oxidative stress induced by ethanol exposure in zebrafish brain

Gallic acid (GA) is a secondary metabolite found in plants. It has the ability to cross the blood-brain barrier and, through scavenging properties, has a protective effect in a brain insult model. Alcohol metabolism generates reactive oxygen species (ROS); thus, alcohol abuse has a deleterious effect on the brain. The zebrafish is a vertebrate often used for screening toxic substances and in acute ethanol exposure models. The aim of this study was to evaluate whether GA pretreatment (24 h) prevents the changes induced by acute ethanol exposure (1 h) in the purinergic signaling pathway in the zebrafish brain via degradation of extracellular nucleotides and oxidative stress. The nucleotide cascade promoted by the nucleoside triphosphate diphosphohydrolase (NTPDase) and 5'-nucleotidase was assessed by quantifying nucleotide metabolism. The effect of GA alone at 5 and 10 mg L^-1 did not change the nucleotide levels. Pretreatment with 10 mg L^-1 GA prevented an ethanol-induced increase in ATP and ADP levels. No significant difference was found between the AMP levels of the two pretreatment groups. Pretreatment with 10 mg L^-1 GA prevented ethanol-enhanced lipid peroxidation and dichlorodihydrofluorescein (DCFH) levels. The higher GA concentration was also shown to positively modulate against ethanol-induced effects on superoxide dismutase (SOD), but not on catalase (CAT). This study demonstrated that GA prevents the inhibitory effect of ethanol on NTPDase activity and oxidative stress parameters, thus consequently modulating nucleotide levels that may contribute to the possible protective effects induced by alcohol and purinergic signaling.

Genus Parkia: Phytochemical, Medicinal Uses, and Pharmacological Properties

The genus Parkia (Fabaceae, Subfamily, Mimosoideae) comprises about 34 species of mostly evergreen trees widely distributed across neotropics, Asia, and Africa. This review aims to provide an overview of the current status of the species from the genus Parkia in terms of its relationship between its phytochemistry and medical uses. Comprehensive information on Parkia species was retrieved from electronic databases, which were Web of Science, ScienceDirect, PubMed, and Google Scholar. This review identified nine species from genus Parkia with properties of medicinal use. They are used traditionally to treat several ailments, such as diabetes, diarrhea, wounds, hypertension, cough, chronic piles, conjunctivitis, and measles. The most common species studied are P. biglobosa, P. speciosa, P. javanica, P. bicolor, P. biglandulosa, P. filicoidea, and P. clappertoniana. A considerable number of secondary metabolites, such as terpenoids, phenolic acids, flavonoids (aglycone and glycosides), and numerous volatile compounds have been identified in this genus, which are responsible for their diverse pharmacological activities. Their extracts, pure compounds and seed lectins have been reported for their anticancer, antimicrobial, antihypertensive, antiulcer, antidiabetic, anti-inflammatory, antioxidant, antimalarial, hepatoprotective, and antidiarrheal activities. The information gathered in this review might be of help for future studies in terms of the current knowledge on the link between the phytochemical components and medicinal uses. This could facilitate more discoveries on its potentials particularly in the pharmacological characteristics and potential to be developed into modern medicines.

Mitochondrial Dysfunction in Diabetic Cardiomyopathy: The Possible Therapeutic Roles of Phenolic Acids

As the powerhouse of the cells, mitochondria play a very important role in ensuring that cells continue to function. Mitochondrial dysfunction is one of the main factors contributing to the development of cardiomyopathy in diabetes mellitus. In early development of diabetic cardiomyopathy (DCM), patients present with myocardial fibrosis, dysfunctional remodeling and diastolic dysfunction, which later develop into systolic dysfunction and eventually heart failure. Cardiac mitochondrial dysfunction has been implicated in the development and progression of DCM. Thus, it is important to develop novel therapeutics in order to prevent the progression of DCM, especially by targeting mitochondrial dysfunction. To date, a number of studies have reported the potential of phenolic acids in exerting the cardioprotective effect by combating mitochondrial dysfunction, implicating its potential to be adopted in DCM therapies. Therefore, the aim of this review is to provide a concise overview of mitochondrial dysfunction in the development of DCM and the potential role of phenolic acids in combating cardiac mitochondrial dysfunction. Such information can be used for future development of phenolic acids as means of treating DCM by alleviating the cardiac mitochondrial dysfunction.

Methanolic extract of Ephedra alata ameliorates cisplatin-induced nephrotoxicity and hepatotoxicity through reducing oxidative stress and genotoxicity

Cisplatin (CP) is a powerful anticancer agent used in the treatment of a diverse type of cancers. Oxidative stress is one of the most important side effects limiting the use of cisplatin. The protective effects of methanolic extract (ME) and ephedrine (EP), major compound, of Ephedra alata on CP-induced damages were here assessed. Treatment with CP-induced nephrotoxicity and hepatotoxicity characterized by biochemical alterations. In fact, using CP reduced significantly glutathione (GSH) levels, enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), and increased malondialdehyde (MDA) content. Nonetheless, CP-treatment induced DNA damage at renal, hepatic, and blood cells and increased interferon gamma (IFNγ) level in serum. Co-treatments of mice with ME normalized relative kidney/body weight, restored biochemical and oxidative stress parameters, reduced DNA damage and IFNγ level. In conclusion, ME exhibited the best protective effect against CP damage compared with ephedrine. This is could be attributed to the presence of polysaccharides, organic acids, flavonoids, and tannins in addition to ephedrine alkaloids. These compounds were reported to play a major role in inhibiting and scavenging free radicals, providing an effective protection against CP- induced oxidative damage. Graphical abstract.

Cocoa Flavonoids Reduce Inflammation and Oxidative Stress in a Myocardial Ischemia-Reperfusion Experimental Model

: Consumption of flavonoid-rich nutraceuticals has been associated with a reduction in coronary events. The present study analyzed the effects of cocoa flavonols on myocardial injury following acute coronary ischemia-reperfusion (I/R). A commercially available cocoa extract was identified by chromatographic mass spectrometry. Nineteen different phenolic compounds were identified and 250 mg of flavan-3-ols (procyanidin) were isolated in 1 g of extract. Oral administration of cocoa extract in incremental doses from 5 mg/kg up to 25 mg/kg daily for 15 days in Sprague Dawley rats (n = 30) produced a corresponding increase of blood serum polyphenols and become constant after 15 mg/kg. Consequently, the selected dose (15 mg/kg) of cocoa extract was administered orally daily for 15 days in a treated group (n = 10) and an untreated group served as control (n = 10). Both groups underwent surgical occlusion of the left anterior descending coronary artery and reperfusion. Cocoa extract treatment significantly reversed membrane peroxidation, nitro-oxidative stress, and decreased inflammatory markers (IL-6 and NF-kB) caused by myocardial I/R injury and enhanced activation of both p-Akt and p-Erk1/2. Daily administration of cocoa extract in rats is protective against myocardial I/R injury and attenuate nitro-oxidative stress, inflammation, and mitigates myocardial apoptosis.

Gallic and carnosic acids improve quality of frozen-thawed ram spermatozoa

The objective was to determine effects of gallic acid (GA) and carnosic acid (CA), present in carob pods and rosemary extract respectively, on frozen-thawed ram spermatozoa. Thirty ejaculates were collected from five Merino rams, pooled, diluted in Tris-based extender and divided into five equal portions containing: 0.05 or 2 mM of GA; 0.05 or 0.2 mM of CA; or no additive (control). Extended semen was equilibrated at +4°C, loaded into straws, held 5 cm above liquid nitrogen for 12 min then plunged. Computer-aided sperm analysis was used to assess motility, whereas flow cytometry was used to assess high mitochondrial membrane potential (HMMP) and percentages of spermatozoa with plasma membrane and acrosome integrity (PMAI). Spermatozoa supplemented with 2 mM GA had greater total motility than control spermatozoa (39.9 ± 3.01 vs. 29.2 ± 1.31%, mean ± SEM, p < .05). The PMAI was greatest in 0.2 mM CA (13.3 ± 0.68%), whereas HMMP was highest in 0.05 mM CA but lowest in control (22.9 ± 4.95 and 11.4 ± 3.64% respectively; p < .05). In conclusion, for cryopreservation of ram semen in Tris-based extender, supplementation with 2 mM GA increased post-thaw motility, whereas supplementation with 0.05 mM CA enhanced mitochondrial function.

Angiotensin-1-converting enzyme inhibition, antioxidant activity, and modulation of cerebral Na+/K+ ATPase by free phenolics of African locust bean (Parkia biglobosa)

AIMS

To investigate the antioxidant activities and effects of free phenols (FPPB) and bound phenols (BPPB) of Parkia biglobosa leaves on some enzymes of neuro-cardiovascular relevance.

METHODS AND RESULTS

HPLC-DAD fingerprinting of FPPB and BPPB, and the antihemolytic, radical (1,1-diphenyl-2 picrylhydrazyl, DPPH; 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid), ABTS) scavenging and ferric reducing antioxidant properties of extracts, were assessed. In addition, the effects of the phenolics on angiotensin-1-converting enzyme (ACE), cerebral acetylcholinesterase/butyrylcholinesterase (AChE/BuChE), and Na+/K+ATPase were determined in vitro. FPPB was more potent than BPPB in terms of ABTS (EC50:4.06 ± 0.3 vs 24.07 ± 2.1 μg/mL) and DPPH (EC50:3.82 ± 0.2 vs 10.22 ± 0.1 μg/mL) radicals scavenged, respectively. The free phenolic extract was a better DPPH. scavenger than ascorbic acid (EC50 = 12.58 ± 0.4 μg/mL; DPPH reference) and compared well with Trolox (EC50:4.44 ± 0.08 μg/mL; ABTS reference). The anti-hemolytic effect of FPPB (36%) and BPPB (53%) was highest at 15 μg/mL but lower than that recorded for ascorbic acid (67% at 10 μg/mL). Even though FPPB (IC50 = 15.35 ± 4.0 μg/mL) and BPPB (IC50 = 46.85 ± 3.3 μg/mL) showed considerably lower ACE-inhibitory effect than ramipril (IC50:0.173 ± 0.04 μg/mL), both extracts demonstrated dose-dependent, significant (p < 0.01/p < 0.05) inhibition of the enzyme. FPPB increased cerebral Na+/K+ATPase activity but neither phenolic extract affects cerebral AChE/BuChE activities. HPLC-DAD revealed catechin, caffeic acid, and quercetin, respectively, as the major phenolics (mg/g) in FPPB (29.85, 30.29, and 17.10) and BPPB (32.70, 30.51, and 19.25).

CONCLUSION

The effects of P biglobosa on ACE and cerebral ATPase are related to its constituent phenolics. ACE inhibition could be an important mechanism underlying the documented hypotensive effect of the plant.

Gallic Acid and Gallates in Human Health and Disease: Do Mitochondria Hold the Key to Success?

Gallic acid and gallate esters are widely used as dietary supplements or additives with clinical significances. Over the last few decades, a large number of publications have been reported stating the antioxidative, antiapoptotic, cardioprotective, neuroprotective, and anticancer properties of gallic acid and gallates, and mostly demonstrated their antioxidative or prooxidative properties influencing the reactive oxygen species (ROS) signaling networks. However, very little focus has been paid to clinical trials, and this restricted their use as a prescribed preventative supplement. Since mitochondria are the principal organelles responsible for ROS generation, we reviewed the existing literature of mitochondria-specific effects of gallates including ROS production, respiration, mitochondrial biogenesis, apoptosis, and the physico-chemical parameters affecting the outcome of gallate supplementation to various health scenarios such as cardiovascular diseases, neurodegeneration, hepatic ailments, or cancers. The major signaling pathways and the molecules targeted by gallic acid and its derivatives have also been discussed with emphasis on mitochondria as the target site. This review provides a better understanding of the effect of gallic acid and gallate esters on mitochondrial functions and in designing effective preventative measures against the onset of various diseases.

Parkia speciosa empty pod prevents hypertension and cardiac damage in rats given N(G)-nitro-l-arginine methyl ester

Parkia speciosa Hassk is a plant found abundantly in Southeast Asia region. Its seeds with or without pods and roots have been used in traditional medicine in this region to treat hypertension. Therefore, we aimed to investigate the potential effect of the plant empty pod extract on hypertension development and changes in heart induced by N(G)-nitro-l-arginine methyl ester (l-NAME) administration in rats. Twenty-four male Sprague Dawley rats were divided into four groups. Groups 1 to 3 were given l-NAME (25mg/kg, intraperitoneally) for 8 weeks. Groups 2 and 3 were also given Parkia speciosa empty pods methanolic extract (800mg/kg, orally) and nicardipine (3mg/kg, orally), concurrently with l-NAME. The last group served as the control. l-NAME reduced plasma nitric oxide level and therefore, increased systolic blood pressure, angiotensin-converting enzyme and NADPH oxidase activities as well as lipid peroxidation in the heart. Parkia speciosa extract and nicardipine treatments had significantly prevented the elevations of blood pressure, angiotensin-converting enzyme, NADPH oxidase activities and lipid peroxidation in the heart induced by the l-NAME. Parkia speciosa extract but not nicardipine prevented the reduction in plasma nitric oxide level caused by l-NAME. In conclusion, Parkia speciosa empty pods methanolic extract has a potential to prevent the development of hypertension possibly by preventing the loss of plasma nitric oxide, as well as has cardioprotective effects by reducing angiotensin-converting enzyme activity and oxidative stress in the heart in rats administered l-NAME.

Baccharis trimera inhibits reactive oxygen species production through PKC and down-regulation p47 phox phosphorylation of NADPH oxidase in SK Hep-1 cells

Baccharis trimera, popularly known as "carqueja", is a native South-American plant possessing a high concentration of polyphenolic compounds and therefore high antioxidant potential. Despite the antioxidant potential described for B. trimera, there are no reports concerning the signaling pathways involved in this process. So, the aim of the present study was to assess the influence of B. trimera on the modulation of PKC signaling pathway and to characterize the effect of the nicotinamide adenine dinucleotide phosphate oxidase enzyme (NOX) on the generation of reactive oxygen species in SK Hep-1 cells. SK-Hep 1 cells were treated with B. trimera, quercetin, or rutin and then stimulated or not with PMA/ionomycin and labeled with carboxy H₂DCFDA for detection of reactive oxygen species by flow cytometer. The PKC expression by Western blot and enzyme activity was performed to evaluate the influence of B. trimera and quercetin on PKC signaling pathway. p47 ^phox and p47 ^phox phosphorylated expression was performed by Western blot to evaluate the influence of B. trimera on p47 ^phox phosphorylation. The results showed that cells stimulated with PMA/ionomycin (activators of PKC) showed significantly increased reactive oxygen species production, and this production returned to baseline levels after treatment with DPI (NOX inhibitor). Both B. trimera and quercetin modulated reactive oxygen species production through the inhibition of PKC protein expression and enzymatic activity, also with inhibition of p47 ^phox phosphorylation. Taken together, these results suggest that B. trimera has a potential mechanism for inhibiting reactive oxygen species production through the PKC signaling pathway and inhibition subunit p47 ^phox phosphorylation of nicotinamide adenine dinucleotide phosphate oxidase.

Antioxidant activity and protective effects of cocoa and kola nut mistletoe ( Globimetula cupulata ) against ischemia/reperfusion injury in Langendorff-perfused rat hearts

Protection against cardiomyocyte damage following ischemia/reperfusion (I/R) injury is highly desirable in patients with ischemic heart disease. Hydromethanol extracts of Globimetula cupulata (mistletoe) growing on cocoa (CGCE) and kola nut (KGCE) trees were assessed for antioxidant content and cardioprotective potential against I/R. Graded concentrations (1–50 μg/mL) of CGCE or KGCE were tested on Langendorff-perfused rat hearts to evaluate the effects on the flow rate, heart rate, and force of cardiac contraction, while another set of hearts were subjected to biochemical analyses. Both extracts showed good antioxidant content and activity, but KGCE (EC₅₀: 24.8±1.8 μg/mL) showed higher hydroxyl radical scavenging activity than CGCE (70.2±4.5 μg/mL). Both extracts at 3 μg/mL reversed (p < 0.001) membrane peroxidation and the significant decrease in nitrite level, coronary flow rate, and superoxide dismutase and catalase activity caused by the I/R cycle. It is concluded that G. cupulata protects against ischemia–reperfusion injury in rat hearts via augmenting endogenous antioxidants and significant restoration of altered hemodynamic parameters.