Annona muricata Linn. leaf as a source of antioxidant compounds with in vitro antidiabetic and inhibitory potential against α-amylase, α-glucosidase, lipase, non-enzymatic glycation and lipid peroxidation.

Annona muricata leaves are used in traditional medicine to manage diabetes mellitus and its complications. The aim of this study was to evaluate the potential in vitro antidiabetic properties of Annona muricata leaf by identifying its main phytochemical constituents and characterizing the phenolic-enriched fractions for their in vitro antioxidant capacity and inhibitory activities against glycoside and lipid hydrolases, advanced glycation end-product formation and lipid peroxidation. Ethanol extract of A. muricata leaf was subjected to a liquid-liquid partitioning and its fractions were used in enzymatic assays to evaluate their inhibitory potential against α-amylase, α-glucosidase and lipase, as well as their antioxidant (DPPH, ORAC, FRAP and Fe2+-ascorbate-induced lipid peroxidation assays) and anti-glycation (BSA-fructose, BSA-methylglyoxal and arginine-methylglyoxal models) capacities. In addition, identification of the main bioactive compounds of A. muricata leaf by HPLC-ESI-MS/MS analysis was carried out. Ethyl acetate (EtOAc) and n-butanol (BuOH) fractions showed, respectively, antioxidant properties (ORAC 3964 ± 53 and 2707 ± 519 μmol trolox eq g-1, FRAP 705 ± 35 and 289 ± 18 μmol trolox eq g-1, and DPPH IC50 4.3 ± 0.7 and 9.3 ± 0.8 μg mL-1) and capacity to reduce liver lipid peroxidation (p < .01). Also, EtOAc and BuOH, respectively, inhibited glycation in BSA-fructose (IC50 45.7 ± 13.5 and 61.9 ± 18.2 μg mL-1), BSA-methylglyoxal (IC50 166.1 ± 21.6 and 413.2 ± 49.5 μg mL-1) and arginine-methylglyoxal (IC50 437.9 ± 89.0 and 1191.0 ± 199.0 μg mL-1) assays, α-amylase (IC50 9.2 ± 2.3 and 6.1 ± 1.6 μg mL-1), α-glucosidase (IC50 413.1 ± 121.1 and 817.4 ± 87.9 μg mL-1) and lipase (IC50 74.2 ± 30.1 and 120.3 ± 50.5 μg.mL-1), and presented lower cytotoxicity, when compared to the other fractions and crude extract. Various biomolecules known as potent antioxidants were identified in these fractions, such as chlorogenic and caffeic acids, procyanidins B2 and C1, (epi)catechin, quercetin, quercetin-hexosides and kaempferol. This study presents new biological activities not yet described for A. muricata, which contributes to the understanding of the potential effectiveness in the use of the A. muricata leaf, especially its polyphenols-enriched fractions, for the management of diabetes mellitus and its complications.

Justino AB ，Miranda NC ，Franco RR ，Martins MM ，Silva NMD ，Espindola FS ... -  《-》

Antidiabetic effects of Syzygium cumini leaves: A non-hemolytic plant with potential against process of oxidation, glycation, inflammation and digestive enzymes catalysis.

Plant materials are commonly used in traditional medicine in order to treat various diseases such as Diabetes mellitus. Some plants, such as Syzygium cumini, have the capability to act controlling oxidative stress and protein glycation besides their potential to decrease hyperglycemia and hyperlipidemia by the inhibition of the catalysis of digestive enzymes. The aim of this study was to evaluate the antioxidant and antiglicant activity of S. cumini leaves fractions, their capacity to inhibit hydrolases and lipase enzymes, as well as the cytotoxicity effects against erythrocytes and comparate these results with isolate quercetin flavonoid. Ethnobotanical researches, carried out by academic studies at the Federal University of Uberlandia, led us to choose S. cumini as a potential plant for treatment of Diabetes mellitus. Fractions from ethanolic extract of S. cumini (hexane/Hex, dichloromethane/DCM, ethyl acetate/EtOAc, n-butanol/ButOH and water/H2O) were used to evaluate their antioxidant (DPPH, ORAC and FRAP) and antiglycant (BSA/fructose, BSA/methylglyoxal and Arginine/Methylglyoxal) activity as well as the inhibitory potential against α-amylase, α-glucosidase and lipase. In addition, identification of the main bioactive compounds of S. cuimini leaves by HPLC-ESIMS/MS analysis was carried out. Our results indicate that all fractions, for exception Hex, present noteworthy antioxidant activity, mainly in EtOAc and ButOH fractions (FRAP 1154.49 ± 67.37 and 1178.27 ± 21.26 μmol trolox eq g-1, respectively; ORAC 1224.63 ± 58.16 and 1313.53 ± 85.23 μmol trolox eq g-1, respectively; DPPH IC50 15.7 ± 2.4 and 23.5 ± 2.7 μg mL-1, respectively). Regarding the antiglycant activity (BSA/fructose and Arginine/Methylglyoxal models), all fraction, for exception Hex, presented inhibition higher than 85%. All fractions were capable to inhibit 100% of α-amylase and the fractions DCM, EtOAc and ButOH inhibited α-glucosidase more than 50%. Regarding the lipase assay, DCM and Hex had the best activity (31.5 ± 14.3 and 44.3 ± 4.5 μg mL-1, respectively). Various biomolecules known as potent antioxidants were identified in these fractions, such as quercetin, kaempferol, luteolin and (Epi)catechin. S. cumini fractions and quercetin presented promising antioxidant and antiglycation properties as well as the ability to inhibit digestive enzymes. This study presents new biological activities not yet described for S. cumini which provide new possibilities for further studies in order to assess the antidiabetic potential of S. cumini fractions especially EtOAc and ButOH.

Franco RR ，Ribeiro Zabisky LF ，Pires de Lima Júnior J ，Mota Alves VH ，Justino AB ，Saraiva AL ，Goulart LR ，Espindola FS ... -  《-》

Peel of araticum fruit (Annona crassiflora Mart.) as a source of antioxidant compounds with α-amylase, α-glucosidase and glycation inhibitory activities.

Annona crassiflora Mart., whose fruit is popularly known as araticum, is a member of the Annonaceae family found in the Brazilian Cerrado. Although this plant has several medicinal uses, its bioactive molecules are not fully understood. A bioguided assay was performed to identify the main bioactive compounds of A. crassiflora fruit peel from the ethanol extract fractions with antioxidant capacity and α-amylase, α-glucosidase and glycation inhibitory activities. Ethyl acetate and n-butanol fractions showed, respectively, higher antioxidant capacity (DPPH IC50 1.5±0.1 and 0.8±0.1μgmL-1, ORAC 3355±164 and 2714±79μmoltroloxeq/g, and FRAP 888±16 and 921±9μmoltroloxeq/g) and inhibitory activities against α-amylase (IC50 4.5±0.8 and 1.7±0.3μgmL-1), α-glucosidase (IC50 554.5±158.6 and 787.8±140.6μgmL-1) and glycation (IC50 14.3±3.3 and 16.0±4.2μgmL-1), and lower cytotoxicity, compared to the other fractions and crude ethanol extract. The HPLC-ESI-MS/MS analysis identified various biomolecules known as potent antioxidants, such as chlorogenic acid, (epi)catechin, procyanidins, caffeoyl-hexosides, quercetin-glucosides and kaempferol. The fruit peel of A. crassiflora, a specie from Cerrado, the Brazilian Savanna, provided a source of antioxidant compounds with properties to block carbohydrate digestive enzymes and formation of glycation products. Thus, there is potential to use the by-products of araticum in order to identify and isolate phytochemicals for application in nutraceutical supplements, food additives and pharmaceuticals products.

Justino AB ，Pereira MN ，Vilela DD ，Peixoto LG ，Martins MM ，Teixeira RR ，Miranda NC ，da Silva NM ，de Sousa RM ，de Oliveira A ，Espindola FS ... -  《-》

Anacardium humile St. Hil as a novel source of antioxidant, antiglycation and α-amylase inhibitors molecules with potential for management of oxidative stress and diabetes.

The substantial increase in diabetes cases worldwide has been a major public health problem, and the use of medicinal plants can be considered an interesting alternative to control the disease and its complications. Anacardium humile St. Hill. (Anacardiaceae) is a typical plant from the Brazilian savanna, popularly known for its antidiarrheal, expectorant, antidiabetic and anti-inflammatory properties, however, few studies have fully described its biological properties. This study aimed to investigate in vitro and ex vivo the antioxidant and antiglycation potential of A. humile ethanolic extract, its organic fractions and three isolated molecules (quercetin, catechin and gallic acid), their capacity to inhibit the glycolytic enzyme α-amylase, as well as their cytotoxic effects against RAW264.7 macrophages. The ethanolic extract of A. humile, its organic fractions and three isolated molecules (catechin, quercetin and gallic acid) were tested for their antioxidant (ORAC, FRAP and DPPH) and antiglycation (BSA/Fructose, BSA/Methylglyoxal, Arginine/Methylglyoxal and Lysine/Methylglyoxal) capacities, and also for its potential to inhibit the enzyme α-amylase. Additionally, bioactive compounds present in the A. humile leaves fractions were elucidated by an HPLC-ESIMS/MS analysis. The analysis showed relevant antioxidant activity of DCM (1264.85 ± 76.90 μM Trolox eq/g ORAC; 216.71 ± 1.04 μM Trolox eq/g FRAP and 3.03 ± 0.08 IC50 μg/mL IC50 DPPH) and EtOAc (1300.11 ± 33.04 ORAC, 236.21 ± 23.86 FRAP and 3.03 ± 0.14 μg/mL IC50 DPPH) fractions and also of the isolated molecules, mainly gallic acid (1291.19 ± 8.41 μM Trolox eq/g ORAC, 1103.52 ± 31.48 μM Trolox eq/g FRAP and 0.78 ± 0.11 μg/mL IC50 DPPH). Concerning the antiglycation activity, all samples inhibited over 88% in the BSA-FRU method. In the BSA-MGO and ARG-MGO methods, the Hex, DCM, EtOAc fractions and the isolated molecule catechin stood out. However, in the LYS-MGO model, only the isolated molecules showed significant results. In α-amylase assay, all fractions, for exception Hex, presented notable inhibition capacity with low IC50 values, especially DCM, EtOAc, ButOH and H2O (IC50 0.56 ± 0.10, 0.84 ± 0.01, 0.74 ± 0.03 and 0.79 ± 0.06 μg/mL, respectively). Tests using hepatic tissue showed a notorious capacity of the DCM, AcOEt and ButOH fractions, as well as of the isolated molecules to inhibit lipid peroxidation and ROS production, and also to preserve thiol groups. Molecules of great antioxidant potential were found in our samples, such as kaempferol, quercetin, catechin, gallic acid and luteolin. A. humile extract and its organic fractions showed promising antioxidant and antiglycation potential and a prominent capacity to inhibit the α-amylase enzyme. Hence, this study presents new results and stimulates further research to elucidate the biological properties of A. humile and its capacity to manage DM and its complications.

Lima Júnior JP ，Franco RR ，Saraiva AL ，Moraes IB ，Espindola FS ... -  《-》

Antioxidant compounds of Kielmeyera coriacea Mart. with α-amylase, lipase and advanced glycation end-product inhibitory activities.

Chronic hyperglycemia and hyperlipidemia are associated with excessive formation of reactive oxygen species and advanced glycation end-products. The present study aimed to evaluate the potential in vitro antidiabetic properties of Kielmeyera coriacea inner bark. The main phytochemical compounds were identified by UHPLC-ESI/MSn and the ethanol extract and its fractions were used to evaluate their antioxidant and anti-glycation capacities, as well as their inhibitory potential against glycoside and lipid hydrolases activities. The polar fractions, especially the n-butanol fraction, had free radical scavenging and quenching properties (ORAC and FRAP values>1800 and 1000 µmol trolox eq/g, respectively, and DPPH IC50<4 µg/mL), and inhibited ROS production (p < 0.01), lipid peroxidation (p < 0.001), glycation (IC50 ~ 10 µg/mL in the BSA-fructose assay; IC50 ~ 200 µg/mL in the BSA-methylglyoxal and arginine-methylglyoxal assays), α-amylase (IC50<0.1 µg/mL) and lipase (IC50<5 µg/mL), with no cytotoxicity. Biomolecules well-known as potent antioxidants were identified for the first time in the inner bark of K. coriacea, such as protocatechuic acid, epicatechin and procyanidins A, B and C. Together, our results support the antioxidant, anti-glycation and glycoside and lipid hydrolases inhibitory properties of the inner bark of K. coriacea, a species found in the Brazilian savanna, which makes it especially useful to combat oxidative stress and hyperglycemia and hyperlipidemia.

Justino AB ，Santana EC ，Franco RR ，Queiroz JS ，Silva HCG ，de Lima JP Júnior ，Saraiva AL ，Martins MM ，Lemos de Morais SA ，de Oliveira A ，Filho LRG ，Aquino FJT ，Espindola FS ... -  《-》