Effects of drying on cholinesterases and angiotensin‐I converting enzyme inhibitory potential and phenolic constituents of African mistletoe (Loranthus bengwensis L) leaves from kolanut host tree

This study investigated the most appropriate drying method (sun drying, oven drying, and shade drying) for mistletoe leaves obtained from kolanut 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 cholinesterases and angiotensin‐I converting enzyme (ACE) and antioxidant activities were determined in vitro. The extracts inhibited acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and ACE in dose‐dependent manner. However, extract from sun‐dried sample exhibited the highest AChE, BChE, and ACE inhibitory effect while extract from shade‐dried sample had the least. Likewise, sun‐dried sample exhibited the highest antioxidant properties as exemplified by Fe2+‐chelating, 1,1‐diphenyl‐2 picrylhdrazyl, OH, and nitric oxide radical scavenging abilities. This study also revealed the presence of 20 phenolic compounds with caffeic acid being the most predominant. Conclusively, kolanut host tree mistletoe leaves can be used as therapeutic agent in the management of Alzheimer's disease and hypertension

Inhibition of key enzymes linked to type 2 diabetes and sodium nitroprusside-induced lipid peroxidation in rat pancreas by water-extractable phytochemicals from unripe pawpaw fruit (Carica papaya)

Background: Various parts of unripe pawpaw (Carica papaya Linn) fruit have been reportedly used for the management or treatment of diabetes mellitus in folklore medicine. Therefore, the present study sought to investigate the inhibitory effects of the aqueous extract of different parts of unripe pawpaw fruit on key enzymes linked to type 2 diabetes (α-amylase and α-glucosidase) and sodium nitroprusside (SNP)-induced lipid peroxidation in rat pancreas in vitro. Methods: The aqueous extracts of the unripe pawpaw (C. papaya) fruit parts were prepared (1:20 w/v) and the ability of the extracts to inhibit α-amylase, α-glucosidase and SNP-induced lipid peroxidation in rat pancreas in vitro was investigated. Results: The results revealed that all the extracts inhibited α-amylase (IC50=0.87–1.11 mg/mL), α-glucosidase (IC50=1.76–2.64 mg/mL) and SNP-induced lipid peroxidation (IC50=1.99–2.42 mg/mL) in a dose-dependent manner. However, combination of the flesh, seed and peel in equal amounts had the highest inhibitory effect on α-amylase and α-glucosidase activities. Conclusions: Strong inhibitory activities of the unripe pawpaw fruit against key enzymes linked to type 2 diabetes and SNP-induced lipid peroxidation in rat pancreas could be part of the mechanism by which unripe pawpaw is used in the management/prevention of diabetes mellitus in folk medicine. However, combining the unripe pawpaw fruit parts in equal amounts exhibited synergistic properties on α-amylase and α-glucosidase inhibitory activitie

Inhibition of α-amylase and α-glucosidase activities by ethanolic extract of Amaranthus cruentus leaf as affected by blanching.

This study investigated the inhibitory effect of Amaranthus cruentus 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 the vegetable on these key enzymes. Fresh leaves of A. cruentus were blanched in hot water for 10 min, and the ethanolic 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. The result revealed that extract of unprocessed A. cruentus leaf reduce Fe3+ to Fe2+ 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 decreased their ability to inhibit α-amylase and α-glucosidase activities. 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 reduced their ability to inhibit both α-amylase and α-glucosidase activity in vitro

Phenolic Extract from Moringa oleifera

This study was designed to determine the antioxidant properties and inhibitory effects of extract from Moringa oleifera leaves on angiotensin-I-converting enzyme (ACE) and arginase activities in vitro. The extract was prepared and phenolic (total phenols and flavonoid) contents, radical (nitric oxide (NO), hydroxyl (OH)) scavenging abilities, and Fe2+-chelating ability were assessed. Characterization of the phenolic constituents was done via high performance liquid chromatography-diode array detection (HPLC-DAD) analysis. Furthermore, the effects of the extract on Fe2+-induced MDA production in rats’ penile tissue homogenate as well as its action on ACE and arginase activities were also determined. The extract scavenged NO∗, OH∗, chelated Fe2+, and inhibited MDA production in a dose-dependent pattern with IC50 values of 1.36, 0.52, and 0.38 mg/mL and 194.23 µg/mL, respectively. Gallic acid, chlorogenic acid, quercetin, and kaempferol were the most abundant phenolic compounds identified in the leaf extract. The extract also inhibited ACE and arginase activities in a dose-dependent pattern and their IC50 values were 303.03 and 159.59 µg/mL, respectively. The phenolic contents, inhibition of ACE, arginase, and Fe2+-induced MDA production, and radical (OH∗, NO∗) scavenging and Fe2+-chelating abilities could be some of the possible mechanisms by which M. oleifera leaves could be used in the treatment and/or management of erectile dysfunction

Impact of drying processes on Bryophyllum pinnatum phenolic constituents and its antiinflammatory and antioxidative activities in human erythrocytes

The effect of drying on the phytoconstituents, antioxidative, and anti-inflammatory properties of Bryophyllum pinnatum leaves was investigated. The phenolic constituents were characterized using HPLC-DAD. The aqueous extraction was done and various assays (Inhibition of membrane stabilization, albumin Denaturation and heatinduced hemolysis, malondialdehyde (MDA), and reduced glutathione (GSH) contents, as well as superoxide dismutase (SOD) activity), were carried out on human erythrocytes. The fresh portion (89.12 µg/ml) exhibited the highest potential to inhibit heat-induced hemolysis compared to the standard drug—Diclofenac (91.51 µg/ml). Freeze-dried sample showed the highest inhibitory potential on albumin denaturation ([Freeze-dried-330.72 µg/ml], [Diclofenac-318.63 µg/ml]) and membrane destabilization ([Freeze-dried-331.93 µg/ml], [Diclofenac-289.57 µg/ml]) when compared with Diclofenac. Similarly, the freeze-dried sample showed the highest GSH and SOD level and lowest MDA level when human erythrocytes challenged with tertiary butyl hydroperoxide (tBHP) were treated with the extract. This study confirms the retention of a considerable quantity of bioactive constituents of plants when freeze-dried

Biological Activities of Essential Oils: From Plant Chemoecology to Traditional Healing Systems

Essential oils are complex mixtures of hydrocarbons and their oxygenated derivatives arising from two different isoprenoid pathways. Essential oils are produced by glandular trichomes and other secretory structures, specialized secretory tissues mainly diffused onto the surface of plant organs, particularly flowers and leaves, thus exerting a pivotal ecological role in plant. In addition, essential oils have been used, since ancient times, in many different traditional healing systems all over the world, because of their biological activities. Many preclinical studies have documented antimicrobial, antioxidant, anti-inflammatory and anticancer activities of essential oils in a number of cell and animal models, also elucidating their mechanism of action and pharmacological targets, though the paucity of in human studies limits the potential of essential oils as effective and safe phytotherapeutic agents. More well-designed clinical trials are needed in order to ascertain the real efficacy and safety of these plant products

Phenolic bioactives as antiplatelet aggregation factors: the pivotal ingredients in maintaining cardiovascular health

Cardiovascular diseases (CVD) are one of the main causes of mortality in the world. The development of these diseases has a specific factor—alteration in blood platelet activation. It has been shown that phenolic compounds have antiplatelet aggregation abilities and a positive impact in the management of CVD, exerting prominent antioxidant, anti-inflammatory, antitumor, cardioprotective, antihyperglycemic, and antimicrobial effects. Thus, this review is intended to address the antiplatelet activity of phenolic compounds with special emphasis in preventing CVD, along with the mechanisms of action through which they are able to prevent and treat CVD. In vitro and in vivo studies have shown beneficial effects of phenolic compound-rich plant extracts and isolated compounds against CVD, despite that the scientific literature available on the antiplatelet aggregation ability of phenolic compounds in vivo is scarce. Thus, despite the current advances, further studies are needed to confirm the cardioprotective potential of phenolic compounds towards their use alone or in combination with conventional drugs for effective therapeutic interventions.N.C.-M. acknowledges the Portuguese Foundation for Science and Technology under the Horizon 2020 Program (PTDC/PSI-GER/28076/2017).info:eu-repo/semantics/publishedVersio

Local condiments from fermented tropical legume seeds modulate activities of critical enzymes relevant to cardiovascular diseases and endothelial function

Investigation into modulatory effects of local condiments produced from fermented legume (African locust bean and soybean) seeds on activities of enzymes relevant to endothelial function and cardiovascular disease (arginase, phosphodiesterase‐5, acetylcholinesterase, and, ecto 5′‐nucleotidase) in vitro was the focus of this study. The condiments were prepared according to traditional methods of fermentation. Thereafter, modulatory effects of aqueous extracts from the condiments on activities of the enzymes were subsequently carried out. Results showed the extracts significantly inhibited activities of arginase, phosphodiesterase‐5 and acetylcholinesterase, while the activity of ecto 5′‐nucleotidase was stimulated at sample concentrations tested. Thus, the observed enzyme modulatory properties exhibited by the condiments could be novel mechanisms to support their use as functional foods and nutraceuticals for the management of cardiovascular disease and associated endothelial dysfunction