Phytochemical investigation and in vitro antioxidant activity of an indigenous medicinal plant Alpinia nigra B.L. Burtt

Objective

To investigate antioxidant potential of methanol extract of Alpinia nigra leaves.

Methods

The study was done by using various in vitro methods such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), nitric oxide and hydrogen peroxide radical scavenging assays. Phytochemical constituents, total phenolic content and total flavonoid content of the extract at different concentrations (10-500 µg/mL) were determined.

Results

Alpinia nigra leaves showed high free radical scavenging activity as evidenced by the low IC₅₀ values in DPPH (64.51 µg/mL), in ABTS (28.32 µg/mL), in nitric oxide (80.02 µg/mL) and in H₂O₂ (77.45 µg/mL) scavenging assays. Furthermore the TPC and TFC of the extract were found to be 69.25 mg gallic acid equivalent per gram of extract and 78.84 mg quercetin equivalent per gram of extract respectively.

Conclusions

The results of present comprehensive analysis demonstrated that Alpinia nigra leaves possess high phenolic, flavonoid contents and potential antioxidant activity, and could be used as a viable source of natural antioxidants and might be exploited for functional foods and neutraceutical applications.     

In vitro antioxidant activities of Solanum surattense leaf extract

Objective

To evaluate the antioxidant activity of alcoholic leaf-extract of Solanum surattense (Solanaceae) (S. surattense).

Methods

Leaf extract were tested for in vitro free radical scavenging assays, such as hydroxyl radical and hydrogen peroxide, inhibition of superoxide anion radical and 2, 2-diphenyl-1-picryl hydrazyl radical (DPPH), total antioxidant activity and reducing ability. Further, total phenolic content of S. surattense was analyzed.

Results

S. surattense extract effectively scavenged free radicals at all different concentrations and showed its potent antioxidant activity. Further, these effects were in a dose dependent manner. Results were compared to standard antioxidants such as butylated hydroxytoluene, ascorbic acid and α-tocopherol.

Conclusions

S. surattense have strong antioxidant potential. Further the study validates the therapeutic benefits of the Indian system of medicine.     

Reduction of hydrogen peroxide-induced erythrocyte damage by Carica papaya leaf extract

Objective

To investigate the in vitro antioxidant potential of Carica papaya (C. papaya) leaf extract and its effect on hydrogen peroxide-induced erythrocyte damage assessed by haemolysis and lipid peroxidation.

Methods

Hydroxyl radical scavenging activities, hydrogen ion scavenging activity, metal chelating activity, and the ferrous ion reducing ability were assessed as antioxidant indices. In the other experiment, human erythrocytes were treated with hydrogen peroxide to induce erythrocyte damage. The extract (at various concentrations) was subsequently incubated with the erythrocytes and later analysed for haemolysis and lipid peroxidation as indices for erythrocyte damage.

Results

Preliminary investigation of the extract showed that the leaf possessed significant antioxidant and free radical scavenging abilities using in vitro models in a concentration dependent manner (P<0.05). The extract also reduced hydrogen peroxide induced erythrocyte haemolysis and lipid peroxidation significantly when compared with ascorbic acid (P<0.05). The IC₅₀ values were 7.33 mg/mL and 1.58 mg/mL for inhibition of haemolysis and lipid peroxidation, respectively. In all cases, ascorbic acid (the reference antioxidant) possessed higher activity than the extract.

Conclusions

The findings show that C. papaya leaves possess significant bioactive potential which is attributed to the phytochemicals which act in synergy. Thus, the leaves can be exploited for pharmaceutical and nutritional purposes.     

Analysis of phytochemical profile of Terminalia arjuna bark extract with antioxidative and antimicrobial properties

Objective

To investigate phytochemical screening, antimicrobial activity and qualitative thin layer chromatographic separation of flavonoid components, antioxidant activity and total flavonoid compound of Terminalia arjuna.

Methods

For phytochemical screening, some common and available standard tests were done. Antimicrobial bioassay was done through agar well diffusion method. Detection of antioxidant activity and flavonoid compounds were done through thin layer chromatography. Total antioxidant activity was measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) in colorimetric method. Aluminum chloride colorimetric method was used for total flavonoid determination.

Results

Phytochemical screening showed the active compounds presence in high concentration, such as phytosterol, lactones, flavonoids, phenolic compounds and tannins and glycosides. The antimicrobial activity of extract showed that greater inhibition zone against Gram negative bacteria than Gram positive bacteria. This methanolic extract showed a promising antioxidant activity, as absorption of DPPH redicles decreased in DPPH free radical scavenging assay. Flavonoids components having antioxidant property present in the methanol extract at a level of 199.00 mg quercetin equivalent/g of dried methanol extract in colorimetric method.

Conclusions

The Terminalia arjuna bark extract revealed the presence of bio-active constituents which are known to exhibit medicinal as well as physiological activities.     

Assessment of effect of hydroalcoholic and decoction methods on extraction of antioxidants from selected Indian medicinal plants

Objective

To assess the effects of extraction methods on antioxidant activities of selected Indian medicinal flora.

Methods

Different parts of plants were extracted by hydroalcoholic and decoction methods using water and various concentrations of methanol (ME) viz. 75%, 50% and 25% ME. The antioxidant activity of all the different extracts was evaluated using two different antioxidant assays viz. 2,2-diphenyl-1-picryl hydrazyl (DPPH) free radical scavenging assay and superoxide anion radical scavenging assay. Total phenol and flavonoid content was also estimated.

Results

The results showed that the extracting solvent significantly altered the antioxidant property estimations of screened plants. High correlations between phenolic compositions and antioxidant activities of extracts were observed. High levels of antioxidant activities were detected in Manilkara zapota (M. zapota) as compared with other screened plants.

Conclusions

The results obtained appear to confirm the effect of different methods on extraction of antioxidants and antioxidant property of M. zapota.     

Phytochemical analysis and in vitro antioxidant acitivity of hydroalcoholic seed extract of Nymphaea nouchali Burm. f.

Objective

To evaluate the phytochemical constituents and the antioxidant activity of hydroalcoholic extract of Nymphaea nouchali seed locally prescribed as a diet for diabetes mellitus.

Methods

The antioxidant and free radical scavenging activity of hydroalcoholic extract of the plant was assessed against 1,1 diphenyl-2-picryl hydrazyl (DPPH), nitric oxide and lipid peroxidation using standard protocols. Total phenolics, flavonoids and tannins were also determined.

Results

Phytochemical analysis revealed the presence of phenols, flavones, tannins, protein, reducing sugars, glycosides, saponins, alkaloids and steroids. The activities of plant extract against DPPH, nitric oxide and lipid peroxidation was concentration dependent with IC₅₀ value of 42.82, 23.58 and 54.65 µg/mL respectively. The total antioxidant capacity was high with 577.73 mg vitamin E/g of the extract and showed a moderately high vitamin C content of 197.22 mg/g. The total tannin content of hydroalcoholic seed extract was high (195.84 GE/g), followed by phenolics (179.56 GE/g) and flavonoids (23.55 QE/g).

Conclusion

Our findings provide evidence that the crude extract of Nymphaea nouchali is a potential source of natural antioxidants and this justifies its use in folkloric medicine.     

Phytochemical,Anti-oxidant and Anthelmintic activities of various leaf extracts of Flacourtia sepiaria Roxb

Objective

The present study was carried out to investigate the phytochemical constituents, in vitro antioxidant potential and anthelmintic activities of Flacourtia sepiaria Roxb leaves.

Methods

The dried powdered leaves of Flacourtia sepiaria were extracted using petroleum ether, chloroform, ethyl acetate and methanol by a soxhlet extractor and preliminary phytochemical screening was performed using standard protocols. All the extract was evaluated for their potential antioxidant activities using test such as DPPH, superoxide anion radical, hydroxyl radical, nitric oxide radical scavenging abilities, ferrous chelating ability and total phenolic and flavanoid content. Anthelmintic activity of extract was screened in adult Indian earthworm model.

Results

Preliminary screening revealed the presence of bioactive compounds especially phenolics, tannins and terpenoids in all extracts. The phenolic and flavanoid content was highest in methanolic extract and lowest in petroleum ether extract. The paralytic (9.46±0.212) and death time (31.43±0.148) of methanolic extract was found to be significant (P<0.05) when compared with paralytic (7.33±0.206) and death time (18.60±0.229) of standard piperazine citrate at 100 mg/mL concentration.

Conclusions

The results of the present study indicate that the leaf extracts of Flacourtia sepiaria exhibited strong antioxidant activity and possess significant anthelmintic activity and thus it is a good source of antioxidant and anthelmintic constituents.     

A comparative study of the antioxidant,antimicrobial, cytotoxic and thrombolytic potential of the fruits and leaves of Spondias dulcis

Objective

To investigate the antioxidant, antimicrobial, cytotoxic and thrombolytic property of the fruits and leaves of Spondias dulcis (S. dulcis).

Methods

Methanolic extracts of fruits and leaves of S. dulcis were partitioned with chloroform and dichloromethane. The antioxidant potential of the crude extract and partitioned fractions were evaluated in terms of total phenolic content, total flavonoid content, DPPH radical scavenging potential, reducing potential and total antioxidant capacity by specific standard procedures. The antimicrobial activity was evaluated using disc diffusion method. The cytotoxicity was evaluated by using brine shrimp lethality bioassay and compared with vincristine sulfate. The thrombolytic activity was compared with streptokinase.

Results

The methanolic fruit extract exhibited the highest phenolic content, flavonoid content and antioxidant capacity, among the other extracts, with the highest DPPH radical scavenging activity at a concentration of 10 µg/mL (IC₅₀: 1.91 µg/mL) and maximum reducing power at a concentration of 100 µg/mL (EC₅₀: 3.58 µg/mL). Though all extract showed moderate antimicrobial activity against the bacterial strains, weak or no activity against fungus. The range of LC₅₀ value of all extracts was 1.335-14.057 µg/mL which was far lower than the cut off index for cytotoxicity. All extracts exhibited statistically significant (P<0.001) thrombolytic activity.

Conclusions

Our study suggested that S. dulcis exhibits antimicrobial activities against a wide variety of strains while it possesses significant antioxidant, cytotoxic and thrombolytic activity.     

Antioxidant potential of phenolic extracts of Mimusops elengi

Objective

To evaluate the antioxidant potential of the phenolic extracts of Mimusops elengi (M. elengi) L. (Sapotaceae).

Methods

The extract of stem bark and seeds of M. elengi were prepared in methanol and acetone:water (7:3). The acetone: water was further partitioned with ethyl acetate and n-butanol. Antioxidant activity of the extracts and partitioned fractions of M. elengi was evaluated in terms of radical scavenging potential (DPPH), inhibition of lipid peroxidation [ferric thiocyanate (FTC)], and total antioxidant activity (phosphomolybdate method). Total phenolics content were calculated using Folin-Ciocalteu reagent.

Results

The stem bark extract partitioned with ethyl acetate exhibited highest amount of total phenols (98.0 mg GAE/g dry weight), among all other extracts, with 92.0% DPPH radical scavenging activity at concentration of 0.5 mg/mL, while methanol extract (stem bark) had maximum inhibition of lipid peroxidation (62.0%) and total antioxidant activity (771.0 mg/g GAE/g). A positive correlation occurred between total phenols and radical scavenging activity (R² = 0.922 9) and total antioxidant activity (R² = 0.945 1).

Conclusions

Our study suggested that antioxidant activity of stembark extract of M. elengi is due the presence of phenolic compounds. Furthermore, the bark extract is a valuable source of natural antioxidants.     

Lupeol: An antioxidant triterpene in Ficus pseudopalma Blanco (Moraceae)

Objective

To assess the antioxidant activity of Ficus pseudopalma Blanco (Moraceae) (F. pseudopalma) and characterize the active components present in it.

Methods

Column chromatography of crude ethanol leaf extract of F. pseudopalma was performed and seven fractions were obtained, labeled as F1, F2, F3, F4, F5, F6, F7. DPPH, FRAP, Griess, Fenton and superoxide radical scavenging assays were performed to assess the antioxidant ability of the fractions. Thin layer chromatography (TLC), high performance liquid chromatography and Fourier transfer infrared spectroscopy (FTIR) were performed to identify and characterize the bioactive component present in each fractions of F. pseudopalma.

Results

DPPH and FRAP assay showed that F5, F6 and F7 exhibited the good proton accepting ability and reducing power as compared to the other fractions. All fractions exhibited a good nitric oxide radical scavenging activity wherein F1, F2 and F3 showed the highest inhibition. However, all of the fractions exhibited a stimulatory activity on hydroxyl and superoxide radicals. Lupeol matched one of the spots on the thin layer chromatography chromatogram of the fractions. Linear gradient high performance liquid chromatography and spiking of lupeol with the fraction revealed the presence of 5.84 mg/L lupeol in F6. Infrared spectra of the fractions revealed the presence of C-C, OH, aromatic C=C and C=O groups.

Conclusions

The identified lupeol in F. pseudopalma may be responsible for the exhibited antioxidant property of the plant. Furthermore, knowing the antioxidant capability of the plant, F. pseudopalma can be developed into products which can help prevent the occurrence of oxidative stress related diseases.     

Antioxidant properties and inhibitory effects of Satureja khozestanica essential oil on LDL oxidation induced-CuSO4 in vitro

Objective

To assess various antioxidative activities of Satureja khozestanica essential oil (SKE) and its effect on oxidation of low density lipoprotein (LDL) induced by CuSO₄ in vitro by monitoring the formation of conjugated dienes and malondialdehyde (MDA).

Methods

The formation of conjugated dienes, lag time and MDA were measured. Inhibition of this Cu-induced oxidation was studied in the presence of several concentrations of SKE. Also total antioxidant activity and free radical scavenging of SKE were determinated.

Results

It was demonstrated that SKE was able to inhibit LDL oxidation and decrease the resistance of LDL against oxidation. The inhibitory effects of SKE on LDL oxidation were dose-dependent at concentrations ranging from 50 to 200 µg/mL. Total antioxidant capacity of SKE was (3.20±0.40) nmol of ascorbic acid equivalents/g SKE. The SKE showed remarkable scavenging activity on 2, 2-diphenyl-picrylhydrazyl, IC₅₀ (5.30±0.11) ng/mL.

Conclusions

This study shows that SKE is a source of potent antioxidants and prevents the oxidation of LDL in vitro and it may be suitable for use in food and pharmaceutical applications.     

Phytochemical analysis and antioxidants activities of aqueous stem bark extract of Schotia latifolia Jacq

Objective

To evaluate the phytochemical constituents and antioxidant activities of aqueous extract of Schotia latifolia (S. latifolia) bark locally used for the treatment of oxidative stress-induced ailments in South Africa.

Methods

The antioxidant and free radical scavenging activity of aqueous extract of the plant was assessed against 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO), 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and the ferric reducing agent. Total phenolics, flavonoids, flavonols and proanthocyanidins were also determined to assess their corresponding effect on the antioxidant activity of this plant.

Results

The activities of plant extract against DPPH, ABTS and NO radicals were concentration dependent with IC₅₀ value of 0.06, 0.05 and 0.05 mg/mL, respectively. The reducing power of the extract was greater than that of butylated hydroxyl toluene (BHT) and ascorbic acid which were used as standard drugs in a concentration dependent manner. The total phenolics content of the aqueous bark extract was (193.33±0.03 TE/g), followed by flavonoids (72.70±0.01 QE/g), proanthocyanidins (48.76±0.00 CE/g) and flavonols (47.76±0.21 QE/g). Phytochemical analysis revealed the presence of percentage tannin (11.40±0.02), alkaloid (9.80±0.01), steroids (18.20±0.01), glycosides (29.80±0.01) and saponins (6.80±0.00). The results exhibited a positive linear correlation between these polyphenols and the free radical scavenging activities.

Conclusions

Our findings provide evidence that the crude aqueous extract of S. latifolia is a potential source of natural antioxidants and this justifies its uses in folkloric medicines.     

Pedalium murex Linn (Pedaliaceae) fruits: a comparative antioxidant activity of its different fractions

Objective

To examine the antioxidant activity and total phenolic content of different solvent fractions of Pedalium murex (P. murex) Linn fruits (Family: Pedaliaceae) as well as the correlation between the total antioxidant capacity and total phenolic content.

Methods

In the present study, the antioxidant activities of P. murex were evaluated using six in-vitro assays, namely total antioxidant assay, DPPH assay, reducing power, nitric oxide scavenging, hydrogen peroxide scavenging and deoxyribose scavenging assays, and total phenol contents were also investigated.

Results

The ethyl acetate (EA) fraction was found to have high levels of phenolic content (298.72±2.09 mg GAE/g). The EA fraction exhibit higher total antioxidant capacity, higher percentage of DPPH radical scavenging activity (135.11±2.95µg/mL), nitric oxide (200.57±4.51µg/mL), hydrogen peroxide (217.91±6.12 µg/mL), deoxyribose (250.01±4.68µg/mL) and higher reducing power. Correlation coefficient (r²=0.914) was found to be significant between total phenolic content and total antioxidant activity.

Conclusions

In general, the results indicate that the EA fractions are rich in phenolic antioxidants with potent free radical scavenging activity implying their importance to human health.     

Chemical composition and antioxidant activity of a Lebanese plant Euphorbia macroclada schyzoceras

Objective

To determine the chemical composition, total phenolic and total flavonoid contents of the crude extracts from leaves and stems of a Lebanese plant Euphorbia macroclada schyzoceras (E. macroclada), and to evaluate their antioxidant potential using DPPH, H₂O₂, and chelating of ferrous ions tests.

Methods

Quantification of the total phenolic and total flavonoid contents of the crude extracts from leaves and stems and the antioxidant activities were evaluated using spectrophotometric analyses. The chemical composition has been estimated using different techniques such as IR, LC/MS and NMR.

Results

Ethanolic extract from leaves of E. macroclada was better than aqueous extract and showed higher content in total phenolic and total flavonoid than found in the stems. On the other hand, using DPPH and H₂O₂ tests, this extract from leaves showed higher antioxidant capacity than aqueous extract. However, using the chelating of ferrous ions test, the antioxidant activity of the aqueous extract of both stems and leaves was stronger than that of ethanolic once. The chemical composition of the whole plant showed the presence of some aromatic compounds and fatty acids.

Conclusions

Both ethanolic and water extracts from both parts of this plant are effective and have good antioxidant power. So, this plant can be used in the prevention of a number of diseases related to oxidative stress.     

Ameliorative effect of alkaloid extract of Cyclea peltata (Poir.) Hook. f. & Thoms. roots (ACP) on APAP/CCl4 induced liver toxicity in Wistar rats and in vitro free radical scavenging property

Objective

To evaluate the hepatoprotective and antioxidant properties of alkaloid extract of Cyclea peltata (C. peltata) against paracetamol/carbon tetra chloride induced liver damage in Wistar rats.

Methods

In vivo paracetamol/carbon tetrachloride induced liver damage in Wistar rats, in vitro free radical scavenging studies, HPTLC estimation of tetrandrine and direct analysis in real time- mass spectrometry of alkaloid extract of C. peltata were used for the validation.

Results

The results showed that pretreatment with alkaloid extract of C. peltata caused significant reduction of serum glutamate pyruvate transaminase, serum glutamate oxaloacetate transaminase, serum alkaline phosphatase, serum cholesterol, liver malondialdehyde levels. The reduced glutathione, catalase, superoxide dismutase levels in liver were increased with alkaloid extract of C. peltata treatment. These results were almost comparable to silymarin and normal control. Histopathological studies also substantiated the biochemical findings. The in vitro hydroxyl, superoxide and DPPH scavenging study of alkaloid extract of C. peltata showed significant free radical scavenging property.

Conclusions

The hepatoprotective property of alkaloid extract of C. peltata against paracetamol/carbon tetrachloride may be due the synergistic action of alkaloids especially tetrandrine, fangchinoline through free radical scavenging and thus preventing oxidative stress.     

Screening of biological activities of Polygonum maritimum L. from Algerian coast

Objective

To investigate the antioxidant and the antibacterial activities of crude extract from aerial part of Polygonum maritimum L. (Polygonaceae) (P. maritimum) and to find new actives biomolecules.

Methods

The whole plant was collected from the Rechgoune coast (West of Algeria), and methanolic crude extract of aerial parts of P. maritimum (PMCE) was prepared. The extract was tested against different bacterial strain and tested for his ability to neutralize free radical (DPPH) and to scavenge the H₂O₂.

Results

PMCE had a very high content of total phenol, which was (352.49±18.03) mg/g dry weight, expressed as gallic acid equivalent. PMCE exhibited excellent antioxidant activity, as measured using DPPH and H₂O₂ scavenging assays. It also showed a high antibacterial activity against gram-positive bacterial strains: Bacillus cereus, Bacillus subtilis and Staphylococcus aureus with an highest MIC of 120 µg/mL.

Conclusions

The antioxidant and antibacterial activity of the PMCE is probably due to phenolic compounds present in the extract. The contemporary presence of antioxidant and antibacterial activities in the PMCE suggests that this plant may be a source of bioactive substances with multifaceted activity.     

In vitro analysis on bactericidal screening and antioxidant potentiality of leaf and root extracts of Thottea siliquosa (Lam.) Ding Hou. An ethnobotanical plant

Objective

Natural products of plant origin are potential source of novel antimicrobial and antioxidative agents. Thottea siliquosa (Lam.) Ding Hou. (T. siliquosa). A medicinal herb used by local tribals for treating various ailments. The present study aims at the phytochemical screening, GC-MS analysis, in vitro antibacterial activity and antioxidant potentiality of root and leaf extracts of T. siliquosa.

Methods

Hot continuous Soxhlet extraction, GC-MS analysis, antibacterial analysis by disc diffusion, microdilution assay and antioxidant potentialities by hydroxyl radical and nitric oxide radical scavenging. The data was statistically analyzed.

Results

Phytochemical screening of the ethyl acetate and methanolic extract of leaf and root revealed the presence of phenols, alkaloids, tannins and saponin. The extract revealed a pool of phytochemicals by comparison with authentic standards from spectral library. Both the extracts has shown their broad spectrum of inhibition against the selected bacteria Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia compared with standard antibiotic drug streptomycin. The extracts showed antioxidant activity by scavenging of free radicals such as hydroxyl and nitric oxide. The IC₅₀ values of the ethyl acetate extracts leaf and root and standard in this assay were 167.5±0.67, 99.4±1.2, 192±2.5 µg/mL respectively. Similarly those methanolic extracts of leaf and root were 269.5±0.89 and 289.1±2.66 µg/mL respectively. Similarly, ethyl acetate and methanolic extracts also caused a moderate dose-dependent inhibition of nitric oxide with an IC₅₀ range 65.5±1.55 to 148 ±3.09 µg/mL. The inhibitory activities were found to be dose dependent.

Conclusion

The present study provides evidence that ethyl acetate and methanol extract of leaf and root of T. siliquosa are potential source of natural antioxidants and bactericidal nature. It is essential that research should continue to isolate and purify the bio active components of this natural plant and use in drug discovery and development.     

Antidiabetic and in vitro antioxidant potential of Hybanthus enneaspermus (Linn) F. Muell in streptozotocin-induced diabetic rats

Objective

To evaluate antidiabetic and antioxidant potential of Hybanthus enneaspermus in different models.

Methods

The oral glucose tolerance test (OGTT) and normoglycemic effect of alcoholic extract of Hybanthus enneaspermus (AHE) were evaluated at a dose of 125, 250 and 500 mg/kg p.o. while hypoglycemic activity and effect on body weight were tested at 250 and 500 mg/kg p.o. per day for 21 days in Streptozotocin (STZ) induced diabetic rats. Further, glucose uptake by hemidiaphram was also evaluated. The total polyphenolic and flavonoid were determined and their correlation with various antioxidant assays was also determined.

Results

The results showed high level of phenolic content in AHE. AHE also exhibited higher total antioxidant capacity, good reducing power and a significant scavenger of reactive oxygen species like DPPH radical, nitric oxide, hydrogen peroxide and deoxyribose. Furthermore there was a significant increase in the body weight and decrease in the blood glucose level on treatment with the AHE. AHE increased glucose uptake on isolated rat hemi-diaphragm compared to control group.

Conclusions

AHE reduce blood glucose level in STZ-induced diabetic model. It does not show significant effect in normoglycemic study but showes significant effect in OGT. AHE has significant antioxidant activity, which may be attributed to high phenolic content.     

Phytochemical screening and free radical scavenging activity of Citrullus colocynthis seeds extracts

Objective

To study the phytochemical screening of different extracts from Citrullus colocynthis (C. colocynthis ) seeds extracts and to assess their antioxidant activity on the DPPH free radical scavenging.

Methods

Phytochemical screening, total content of polyphenols and flavonoids of C. colocynthis seeds extracts, including a crude aqueous extract (E1), a defatted aqueous extract (E2), a hydromethanolic extract (HM), an ethyl acetate extract (EA) and a n-butanol extract (n-B) was carried out according to the standard methods and to assess their corresponding effect on the antioxidant activity of this plant.

Results

None of these extracts contained detectable amount of alkaloid, quinone, antraquinone, or reducing sugar. Catechic tannins and flavonoids were abundant in E1, HM and EA, whilst terpenoids were abundantly present in E1 and n-B but only weekly in HM. Coumarins were found in E2, EA and n-B. Polyphenols, expressed as gallic acid equivalent, amounted, per 100 g plant matter, to 329, 1002 and 150 mg in EA, HM an E1 respectively. Flavonoids, expressed as catechin equivalent, amounted, per 100 g plant matter to 620, 241 and 94 mg in EA, HM and E1 respectively. Comparable values were found in n-B and E1, with lower values in E2. Quercetin, myricetin and gallic acid were found in the EA and HM extracts by thin layer chromatography, The antioxidative effect of these extracts yielded, when tested at a concentration of 2 000 µg/mL in a 1,1-diphenyl-2-picrylhydrazyl assay, a reducing percentage of 88.8% with EA, 74.5% with HM and 66.2% with E1, and corresponding IC₅₀ of 350, 580 and 500 µg/mL as compared to 1.1 µg/mL for ascorbic acid.

Conclusions

These qualitative and quantitative analytical data document the presence in C. colocynthis extracts of such chemical compounds as flavonoids responsible for the antioxidant activity, as well as other biological activities of this plant.     

Antiglycation,antioxidant and toxicological potential of polyphenol extracts of alligator pepper,ginger and nutmeg from Nigeria

Objective

To evaluate the antioxidant and antiglycation potential of polyphenols from three spices; alligator pepper, ginger and nutmeg.

Methods

Polyphenol extracts of these spices were subjected to brine-shrimp lethality assay, phytotoxicity test, DPPH and superoxide anion radical scavenging as well as BSA-glucose antiglycation assay.

Results

Results obtained showed that polyphenol extract of ginger has the highest antioxidant potential with IC₅₀ 0.075 and 0.070 mg/mL for DPPH and superoxide anion radical scavenging assay while alligator pepper displayed highest antiglycation activity with IC₅₀ 0.125 mg/mL. However, nutmeg extract exhibited weakest cytotoxic and phytotoxic potential with LD₅₀ 4359.70 and 1490 µg/mL respectively.

Conclusions

It can be concluded that the polyphenol extracts of alligator pepper, ginger and nutmeg displayed good antioxidant as well as antiglycation potential and are safe for consumption.