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Hypoglycemic Effect of the Methanol flower Extract of Piper Claussenianum and the Major Constituent 2',6'-dihydroxy-4'-methoxychalcone in Streptozotocin Diabetic Rats.

Marques AM, Pereira SL, Paiva RA, Cavalcante CV, Sudo SZ, Tinoco LW, Moreira DL, Guimaraes EF, Sudo RT, Kaplan MA, Sudo GZ - Indian J Pharm Sci (2015 Mar-Apr)

Bottom Line: The major compound 2',6'-dihydroxy-4'-methoxychalcone was also tested.The results suggest this chalcone is one of the metabolite responsible for the blood glucose levels reduction in rats with streptozotocin-induced diabetes.The inflorescence crude extract of P. claussenianum was found to be composed mainly by flavonoids and may be a potential natural source of compounds with hypoglycemic properties.

View Article: PubMed Central - PubMed

Affiliation: Núcleo de Pesquisas de Produtos Naturais, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

ABSTRACT
Piper claussenianum inflorescences crude methanol extract was tested for hypoglycemic effect in streptozotocin-induced diabetic rats. The blood glucose levels of rats treated with methanol extract were reduced from 318.4±28.1 mg/dl before treatment to 174.2±38.3 mg/dl after 12 days of treatment (P<0.05). Phytochemical studies were carried out on inflorescences methanol crude extract in order to investigate the possible metabolites responsible for the pharmacological properties of the extract. After chromatographic procedures, three flavonoids were isolated and characterized. The major compound 2',6'-dihydroxy-4'-methoxychalcone was also tested. Rats that received the chalcone content also displayed a reduction in blood glucose levels from 277.4±7.7 mg/dl before treatment to 158.8±9.2 mg/dl after 12 days of treatment (P<0.05). The results suggest this chalcone is one of the metabolite responsible for the blood glucose levels reduction in rats with streptozotocin-induced diabetes. The inflorescence crude extract of P. claussenianum was found to be composed mainly by flavonoids and may be a potential natural source of compounds with hypoglycemic properties.

No MeSH data available.


Related in: MedlinePlus

Isolated compounds from Piper claussenianum inflorescence.
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Figure 1: Isolated compounds from Piper claussenianum inflorescence.

Mentions: Further chromatographic separations of the inflorescences extract on silica gel yielded flavonoid rich fractions. The fractions 28-34 afforded compound 1 as orange needle shaped crystals by recrystallization from MeOH. Fractions 22-24 yielded compound 2 as yellow needle shaped crystals, while the fraction 82-84 afforded compound 3 as colorless needle-shaped crystals. The 1H NMR spectrum showed two doublets at δ 5.87 (J=2.3 Hz, 1H) and 5.92 (J=2.3 Hz, 1H) for compound 1; δ 5.87 (J=2.1 Hz, 1H) and 5.98 (J=2.1 Hz, 1H) for compound 2 and δ 5.97 (J=2.3 Hz, 1H) and 6.04 (J=2.3 Hz, 1H) for compound 3. These are associated to their corresponding carbons (δ 95.25 and 96.90 to 1; δ 92,40 and 96.30 to 2 and δ 83.75 and 96.70 to 3). The chemical shift assignments were based on HSQC and HMBC and were assigned as H-6 and H-8 in the ring A of the flavanones and H-1’ and H-5’ of the chalcone. The related carbons shifts are in agreement to the oxygenated meta substituents. A hydroxyl group chelated to carbonyl group was found in compound 1 and 2 in δ 12.5 and δ 12.2, respectively. Peaks in δ 10.5 and δ 10.3 were observed in the 1H NMR spectra of 2 and 3, respectively. These data associated to the HMBC and 13 C correlations possibly were related to hydroxyl groups in C-5 (δ 165.5) and C-‘6 (δ 164.7) for compounds 2 and 3, respectively. The 1H NMR data were associated to the signals at δ 5.55 (dd, J=13.0 and 2.4 Hz, H-2), 2.77 (dd, J=17.1 and 2.2 Hz, H-3a), 3.22 (dd, J=17.2 and 13.5 Hz, H-3b), δ 5.33 (dd, J=13.0 and 2.9 Hz, H-2), 2.69 (dd, J=17.1 and 2.3 Hz, H-3a), 2.98 (dd, J=17.0 and 13.2 Hz, H-3b) corresponding to the compounds 2 and 3, respectively. Since no substitution was observed in B ring of all compounds, no AB systems were detected as characteristic of a para-dissustituted aromatic rings. LREIMS analyses showed molecular ion-peaks at m/z 270 (52%) for compound 1 (C16H14O4), m/z 256 (100%) for compound 2 (C15H12O4) and m/z 270 (51%) for compound 3 (C16H14O4). The 1H NMR spectrum obtained for these compounds were found in agreement to the compound 1 compound 2, and compound 3, respectively, (fig. 1). These data led us to characterize compound 1 as 2’,6’-dihydroxy-4’-methoxychalcone; 2 as 5,7-dihydroxydihydroflavone (pinocembrin) and 3 as 5-methoxy-7-hydroxydihydroflavone (alpinetin)[567818]. The quantitative analyses of compounds 1, 2 and 3 were carried out using HPLC-UV (HPLC-DAD-UV Shimadzu) instead of LC-MS, since these compounds were present at >0.05% (w/w). The pure isolated compounds were used as standards. Injections of each sample (10 μl) were analyzed in triplicate using the same conditions described for the LC separations. Areas under the curve from experimental peaks in the chromatogram were determined and the percent weight of each compound present was calculated based on a standard curve and amount (μg) of extract injected onto the column. Data were only used if their relative standard deviations (RSD, %; (mean–standard deviation)/mean)×100) were <5%. The three isolated measured flavonoids comprise 6.9% of the weight raw extract of P. claussenianum inflorescences. The compound 1 was found in (2.5%), the compound 2 (2.8%) while the compound 3 was found in smaller amount (1.6%).


Hypoglycemic Effect of the Methanol flower Extract of Piper Claussenianum and the Major Constituent 2',6'-dihydroxy-4'-methoxychalcone in Streptozotocin Diabetic Rats.

Marques AM, Pereira SL, Paiva RA, Cavalcante CV, Sudo SZ, Tinoco LW, Moreira DL, Guimaraes EF, Sudo RT, Kaplan MA, Sudo GZ - Indian J Pharm Sci (2015 Mar-Apr)

Isolated compounds from Piper claussenianum inflorescence.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4442476&req=5

Figure 1: Isolated compounds from Piper claussenianum inflorescence.
Mentions: Further chromatographic separations of the inflorescences extract on silica gel yielded flavonoid rich fractions. The fractions 28-34 afforded compound 1 as orange needle shaped crystals by recrystallization from MeOH. Fractions 22-24 yielded compound 2 as yellow needle shaped crystals, while the fraction 82-84 afforded compound 3 as colorless needle-shaped crystals. The 1H NMR spectrum showed two doublets at δ 5.87 (J=2.3 Hz, 1H) and 5.92 (J=2.3 Hz, 1H) for compound 1; δ 5.87 (J=2.1 Hz, 1H) and 5.98 (J=2.1 Hz, 1H) for compound 2 and δ 5.97 (J=2.3 Hz, 1H) and 6.04 (J=2.3 Hz, 1H) for compound 3. These are associated to their corresponding carbons (δ 95.25 and 96.90 to 1; δ 92,40 and 96.30 to 2 and δ 83.75 and 96.70 to 3). The chemical shift assignments were based on HSQC and HMBC and were assigned as H-6 and H-8 in the ring A of the flavanones and H-1’ and H-5’ of the chalcone. The related carbons shifts are in agreement to the oxygenated meta substituents. A hydroxyl group chelated to carbonyl group was found in compound 1 and 2 in δ 12.5 and δ 12.2, respectively. Peaks in δ 10.5 and δ 10.3 were observed in the 1H NMR spectra of 2 and 3, respectively. These data associated to the HMBC and 13 C correlations possibly were related to hydroxyl groups in C-5 (δ 165.5) and C-‘6 (δ 164.7) for compounds 2 and 3, respectively. The 1H NMR data were associated to the signals at δ 5.55 (dd, J=13.0 and 2.4 Hz, H-2), 2.77 (dd, J=17.1 and 2.2 Hz, H-3a), 3.22 (dd, J=17.2 and 13.5 Hz, H-3b), δ 5.33 (dd, J=13.0 and 2.9 Hz, H-2), 2.69 (dd, J=17.1 and 2.3 Hz, H-3a), 2.98 (dd, J=17.0 and 13.2 Hz, H-3b) corresponding to the compounds 2 and 3, respectively. Since no substitution was observed in B ring of all compounds, no AB systems were detected as characteristic of a para-dissustituted aromatic rings. LREIMS analyses showed molecular ion-peaks at m/z 270 (52%) for compound 1 (C16H14O4), m/z 256 (100%) for compound 2 (C15H12O4) and m/z 270 (51%) for compound 3 (C16H14O4). The 1H NMR spectrum obtained for these compounds were found in agreement to the compound 1 compound 2, and compound 3, respectively, (fig. 1). These data led us to characterize compound 1 as 2’,6’-dihydroxy-4’-methoxychalcone; 2 as 5,7-dihydroxydihydroflavone (pinocembrin) and 3 as 5-methoxy-7-hydroxydihydroflavone (alpinetin)[567818]. The quantitative analyses of compounds 1, 2 and 3 were carried out using HPLC-UV (HPLC-DAD-UV Shimadzu) instead of LC-MS, since these compounds were present at >0.05% (w/w). The pure isolated compounds were used as standards. Injections of each sample (10 μl) were analyzed in triplicate using the same conditions described for the LC separations. Areas under the curve from experimental peaks in the chromatogram were determined and the percent weight of each compound present was calculated based on a standard curve and amount (μg) of extract injected onto the column. Data were only used if their relative standard deviations (RSD, %; (mean–standard deviation)/mean)×100) were <5%. The three isolated measured flavonoids comprise 6.9% of the weight raw extract of P. claussenianum inflorescences. The compound 1 was found in (2.5%), the compound 2 (2.8%) while the compound 3 was found in smaller amount (1.6%).

Bottom Line: The major compound 2',6'-dihydroxy-4'-methoxychalcone was also tested.The results suggest this chalcone is one of the metabolite responsible for the blood glucose levels reduction in rats with streptozotocin-induced diabetes.The inflorescence crude extract of P. claussenianum was found to be composed mainly by flavonoids and may be a potential natural source of compounds with hypoglycemic properties.

View Article: PubMed Central - PubMed

Affiliation: Núcleo de Pesquisas de Produtos Naturais, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

ABSTRACT
Piper claussenianum inflorescences crude methanol extract was tested for hypoglycemic effect in streptozotocin-induced diabetic rats. The blood glucose levels of rats treated with methanol extract were reduced from 318.4±28.1 mg/dl before treatment to 174.2±38.3 mg/dl after 12 days of treatment (P<0.05). Phytochemical studies were carried out on inflorescences methanol crude extract in order to investigate the possible metabolites responsible for the pharmacological properties of the extract. After chromatographic procedures, three flavonoids were isolated and characterized. The major compound 2',6'-dihydroxy-4'-methoxychalcone was also tested. Rats that received the chalcone content also displayed a reduction in blood glucose levels from 277.4±7.7 mg/dl before treatment to 158.8±9.2 mg/dl after 12 days of treatment (P<0.05). The results suggest this chalcone is one of the metabolite responsible for the blood glucose levels reduction in rats with streptozotocin-induced diabetes. The inflorescence crude extract of P. claussenianum was found to be composed mainly by flavonoids and may be a potential natural source of compounds with hypoglycemic properties.

No MeSH data available.


Related in: MedlinePlus