PHYTOCHEMICAL AND BIOLOGICAL STUDIES ON CERTAIN PLANTS BELONGING TO FAMILY BIGNONIACEAE
Nada Mohamed Mahmoud Mohamed Mostafa;
Abstract
Family Bignoniaceae includes 120 genera with 800 species mainly distributed within tropical floras of the world with lesser representation in temperate regions; however, some species are used worldwide as ornamentals. It consists mainly of woody trees, shrubs, and lianas (Yff et al., 2002; Da Silveira et al., 2012).
Bignoniaceae includes attractive ornamental flowering trees and lianas and produce hard and durable timbers, many pharmacologically active chemicals, various products used in local handicrafts, and even a few edible seeds and fruits (Pattnaik et al., 1997).
Many woody representatives of Bignoniaceae are well known for their use in the timber industry (e.g. Tabebuia, Cybistax, Paratecoma, Stereospermum, Parmentiera, Jacaranda, Catalpa) or as ornamentals (e.g. Jacaranda, Catalpa, Spathodea). Some genera occur mainly as lianas such as Pandorea and Macfadyena (Parker, 2008).
Chemical constituents recognized in the family are naphthoquinones of the lapachol type, iridoid glucosides, alkaloids, flavones, triterpenes, polyphenols, tannins and seed oils (Hegnauer, 1964; Gachet and Schuhly, 2009).
The genus Jacaranda, an important representative of the tribe Tecomeae in the family Bignoniaceae, is interesting from both biological and chemical perspectives. Jacaranda contains 49 species around the world that are native to Central and South America and the Caribbean. Out of the 49 Jacaranda species, 39 taxa are endemic to Brazil. Its main secondary metabolites identified are triterpenes, quinones, flavonoids, and acetosides. Members of this genus are well known in traditional ethnobotany for their pharmacological potential and promising activities, especially in the field of tropical diseases, skin problems and venereal infections (Gachet and Schuhly, 2009).
Genus Pyrostegia is a small but diverse genus of four species in the tribe Bignonieae (Bignoniaceae). The genus is native to South America, with P. venusta (Ker Gawl.) Miers frequently cultivated throughout the tropics (Pool, 2008).
Though many phytochemical constituents and valuable medicinal uses were reported from different plants belonging to family Bignoniaceae, yet it is felt necessary to explore more, so the aim of this thesis was to investigate the phytoconstituents as well as the biological activity of J. acutifolia, to validate some of its ethnopharmacological uses and to compare its activity with another plant of the same family, P. venusta.
The preliminary phytochemical screening of J. acutifolia leaves revealed its richness with a variety of compounds, including volatile oil, sterols, tannins and flavonoids; these compounds were reported to have a variety of biological activities including antioxidant, antimicrobial, anti-inflammatory, hepatoprotective and antihyperglycemic effects.
The present study comprises three chapters:
Chapter I
Biological Studies of J. acutifolia and P. venusta Leaves and / or Flowers
I. Biological Investigation of the Methanol Soluble Fraction of Aqueous Extracts of J. acutifolia and P. venusta Leaves
Biological activities of the methanol extract of J. acutifolia and P. venusta leaves were investigated regarding:
1. In vitro antioxidant assay (DPPH assay).
2. In vivo studies including
2.1. Hepatoprotective activity.
2.2. Antihyperglycemic activity.
1. In Vitro Antioxidant Assay (DPPH Assay)
The antioxidant activity of methanol soluble fractions of aqueous extracts of both J. acutifolia and P. venusta leaves revealed potent antioxidant activity in vitro through DPPH assay where they showed EC50 of 0.43 and 0.4 mg/mL, respectively.
The scavenging percentages of J. acutifolia leaf extract to DPPH were 25, 45 and 75% at concentrations of 0.2, 0.4, and 0.6 mg/mL respectively. While, the scavenging percentages of P. venusta leaf extract to DPPH were 20, 50 and 77% at concentrations of 0.2, 0.4, and 0.6 mg/mL respectively. The results were compared to a reference antioxidant compound, vitamin E which displayed % DPPH scavenging activity of 15, 22 and 27% at the same concentrations.
From the previous results, it was clear that J. acutifolia and P. venusta leaves extracts produced strong inhibition of DPPH radicals, indicating that their powerful antioxidant capacity in vitro, which was superior than vitamin E, the used antioxidant reference compound.
2. In Vivo Studies in Rats
2.1. Hepatoprotective Activity
The tested extracts reversed the hepatotoxicity significantly as evident from marked reduction in the TAM-induced increase in serum ALT and AST activities and significant reduction in the tremendously increased levels of TBARS and TNF-α as a result of TAM administration. These findings support our previous results indicating the antioxidant, hepatoprotective and anti-inflammatory activities exhibited by J. acutifolia and P. venusta leaves extracts.
2.2. Antihyperglycemic Activity
The tested extracts reversed the hyperglycemia significantly as evident from marked reduction in the STZ-induced increase in FBG level and amelioration in the tremendously decreased level of serum insulin as a result of STZ administration. These results were comparable to that of a reference antihyperglycemic drug, GLB.
II. Antimicrobial Activity of J. acutifolia Essential Oils of Flowers, Leaves and Hexane Extract of the Leaves
The antimicrobial activities against food-borne pathogens and fungi were studied by the agar diffusion method. The minimum inhibitory concentrations (MIC) were determined against standard antibiotics (penicillin, gentamicin and nystatin).
The flowers oil showed a substantial antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans with MIC values ranging from 0.9 up to 10.9 mg/mL, while it showed moderate antimicrobial activity against Shigella flexneri and Salmonella typhimurium. The leaves oil showed substantial antimicrobial activity against Staphylococcus aureus and Escherichia coli with MIC values of 2.2 and 2.9 mg/mL respectively, and moderate antimicrobial activity against Candida albicans, Salmonella typhimurium and Shigella flexneri. The hexane extract showed moderate antimicrobial activities against all tested microorganisms, with MIC values ranging from 3.5 to 10.2 mg/mL.
As a conclusion, the leaves essential oil exhibited potential antimicrobial activity against foodborne bacteria and yeast, which was superior to either the flowers oil or the leaves hexane extract, and this in-vitro activity makes the local traditional uses of J. acutifolia rational.
Bignoniaceae includes attractive ornamental flowering trees and lianas and produce hard and durable timbers, many pharmacologically active chemicals, various products used in local handicrafts, and even a few edible seeds and fruits (Pattnaik et al., 1997).
Many woody representatives of Bignoniaceae are well known for their use in the timber industry (e.g. Tabebuia, Cybistax, Paratecoma, Stereospermum, Parmentiera, Jacaranda, Catalpa) or as ornamentals (e.g. Jacaranda, Catalpa, Spathodea). Some genera occur mainly as lianas such as Pandorea and Macfadyena (Parker, 2008).
Chemical constituents recognized in the family are naphthoquinones of the lapachol type, iridoid glucosides, alkaloids, flavones, triterpenes, polyphenols, tannins and seed oils (Hegnauer, 1964; Gachet and Schuhly, 2009).
The genus Jacaranda, an important representative of the tribe Tecomeae in the family Bignoniaceae, is interesting from both biological and chemical perspectives. Jacaranda contains 49 species around the world that are native to Central and South America and the Caribbean. Out of the 49 Jacaranda species, 39 taxa are endemic to Brazil. Its main secondary metabolites identified are triterpenes, quinones, flavonoids, and acetosides. Members of this genus are well known in traditional ethnobotany for their pharmacological potential and promising activities, especially in the field of tropical diseases, skin problems and venereal infections (Gachet and Schuhly, 2009).
Genus Pyrostegia is a small but diverse genus of four species in the tribe Bignonieae (Bignoniaceae). The genus is native to South America, with P. venusta (Ker Gawl.) Miers frequently cultivated throughout the tropics (Pool, 2008).
Though many phytochemical constituents and valuable medicinal uses were reported from different plants belonging to family Bignoniaceae, yet it is felt necessary to explore more, so the aim of this thesis was to investigate the phytoconstituents as well as the biological activity of J. acutifolia, to validate some of its ethnopharmacological uses and to compare its activity with another plant of the same family, P. venusta.
The preliminary phytochemical screening of J. acutifolia leaves revealed its richness with a variety of compounds, including volatile oil, sterols, tannins and flavonoids; these compounds were reported to have a variety of biological activities including antioxidant, antimicrobial, anti-inflammatory, hepatoprotective and antihyperglycemic effects.
The present study comprises three chapters:
Chapter I
Biological Studies of J. acutifolia and P. venusta Leaves and / or Flowers
I. Biological Investigation of the Methanol Soluble Fraction of Aqueous Extracts of J. acutifolia and P. venusta Leaves
Biological activities of the methanol extract of J. acutifolia and P. venusta leaves were investigated regarding:
1. In vitro antioxidant assay (DPPH assay).
2. In vivo studies including
2.1. Hepatoprotective activity.
2.2. Antihyperglycemic activity.
1. In Vitro Antioxidant Assay (DPPH Assay)
The antioxidant activity of methanol soluble fractions of aqueous extracts of both J. acutifolia and P. venusta leaves revealed potent antioxidant activity in vitro through DPPH assay where they showed EC50 of 0.43 and 0.4 mg/mL, respectively.
The scavenging percentages of J. acutifolia leaf extract to DPPH were 25, 45 and 75% at concentrations of 0.2, 0.4, and 0.6 mg/mL respectively. While, the scavenging percentages of P. venusta leaf extract to DPPH were 20, 50 and 77% at concentrations of 0.2, 0.4, and 0.6 mg/mL respectively. The results were compared to a reference antioxidant compound, vitamin E which displayed % DPPH scavenging activity of 15, 22 and 27% at the same concentrations.
From the previous results, it was clear that J. acutifolia and P. venusta leaves extracts produced strong inhibition of DPPH radicals, indicating that their powerful antioxidant capacity in vitro, which was superior than vitamin E, the used antioxidant reference compound.
2. In Vivo Studies in Rats
2.1. Hepatoprotective Activity
The tested extracts reversed the hepatotoxicity significantly as evident from marked reduction in the TAM-induced increase in serum ALT and AST activities and significant reduction in the tremendously increased levels of TBARS and TNF-α as a result of TAM administration. These findings support our previous results indicating the antioxidant, hepatoprotective and anti-inflammatory activities exhibited by J. acutifolia and P. venusta leaves extracts.
2.2. Antihyperglycemic Activity
The tested extracts reversed the hyperglycemia significantly as evident from marked reduction in the STZ-induced increase in FBG level and amelioration in the tremendously decreased level of serum insulin as a result of STZ administration. These results were comparable to that of a reference antihyperglycemic drug, GLB.
II. Antimicrobial Activity of J. acutifolia Essential Oils of Flowers, Leaves and Hexane Extract of the Leaves
The antimicrobial activities against food-borne pathogens and fungi were studied by the agar diffusion method. The minimum inhibitory concentrations (MIC) were determined against standard antibiotics (penicillin, gentamicin and nystatin).
The flowers oil showed a substantial antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans with MIC values ranging from 0.9 up to 10.9 mg/mL, while it showed moderate antimicrobial activity against Shigella flexneri and Salmonella typhimurium. The leaves oil showed substantial antimicrobial activity against Staphylococcus aureus and Escherichia coli with MIC values of 2.2 and 2.9 mg/mL respectively, and moderate antimicrobial activity against Candida albicans, Salmonella typhimurium and Shigella flexneri. The hexane extract showed moderate antimicrobial activities against all tested microorganisms, with MIC values ranging from 3.5 to 10.2 mg/mL.
As a conclusion, the leaves essential oil exhibited potential antimicrobial activity against foodborne bacteria and yeast, which was superior to either the flowers oil or the leaves hexane extract, and this in-vitro activity makes the local traditional uses of J. acutifolia rational.
Other data
| Title | PHYTOCHEMICAL AND BIOLOGICAL STUDIES ON CERTAIN PLANTS BELONGING TO FAMILY BIGNONIACEAE | Other Titles | دراسة فيتوكيميائية و بيولوجية لبعض النباتات التي تنتمي للعائلة البجنونية | Authors | Nada Mohamed Mahmoud Mohamed Mostafa | Issue Date | 2014 |
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