Hepatoprotective effect of methanol extract of Agave americana leaves on paracetamol induced hepatotoxicity in Wistar albino rats

BACKGROUND

Ethiopians locally treat liver illnesses with A. Americana. Available literature demonstrates this. However, there are few in-vivo investigations that provide supporting data. The aim of this study was to evaluate the hepatoprotective effects of methanolic extract of Agave americana leaves on rat liver damage caused by paracetamol.

METHODS

The acute oral toxicity test was conducted in accordance with OECD-425 recommendations. The approach outlined by Eesha et al. (Asian Pac J Trop Biomed 4:466-469,  2011) was used to test the hepatoprotective activity. Wistar male rats weighing between 180 and 200 g were used, and six groups with seven animals each were formed. Group I received treatment with gum acacia (2%) at a dose of 2 ml/kg p.o. daily for 7 days. Rats in group II were treated with 2% gum acacia orally daily for seven days along with a single dose of paracetamol (2 mg/kg) p.o. on 7^th day. Silymarin (50 mg/kg) was given orally to Group III for 7 days. Plant extract doses of 100 mg/kg, 200 mg/kg, and 400 mg/kg were administered orally to Groups IV -VI for seven days, respectively. All rats in groups III-VI were treated with paracetamol (2 mg/kg) 30 min following extract administration. Blood samples were obtained from the cardiac puncture after paracetamol had been used for 24 h to induce toxicity. Serum biomarkers (AST, ALT, ALP, and total bilirubin) were estimated. A histopathological investigation was also done.

RESULTS

No toxicity symptoms or animal fatalities were recorded during the acute toxicity study. The values of AST, ALT, ALP, and total bilirubin were all substantially raised by paracetamol. Significant hepatoprotective effects were obtained by pretreatment with A. americana extract. Histopathological examination of the liver tissues of paracetamol control group represented the presence of marked foci of mononuclear infiltration in the hepatic parenchyma tissue, sinusoid, and around central vein, as well as disorganization of hepatic plates, necrosis, and fatty changes of hepatocytes. Pretreatment with A. americana extract reversed these alterations. Results of the methanolic extract of A. americana were comparable to Silymarin.

CONCLUSION

The current investigation supports the hepatoprotective properties of Agave americana methanolic extract.

Overexpression of an Agave Phosphoenolpyruvate Carboxylase Improves Plant Growth and Stress Tolerance

It has been challenging to simultaneously improve photosynthesis and stress tolerance in plants. Crassulacean acid metabolism (CAM) is a CO2-concentrating mechanism that facilitates plant adaptation to water-limited environments. We hypothesized that the ectopic expression of a CAM-specific phosphoenolpyruvate carboxylase (PEPC), an enzyme that catalyzes primary CO2 fixation in CAM plants, would enhance both photosynthesis and abiotic stress tolerance. To test this hypothesis, we engineered a CAM-specific PEPC gene (named AaPEPC1) from Agave americana into tobacco. In comparison with wild-type and empty vector controls, transgenic tobacco plants constitutively expressing AaPEPC1 showed a higher photosynthetic rate and biomass production under normal conditions, along with significant carbon metabolism changes in malate accumulation, the carbon isotope ratio δ13C, and the expression of multiple orthologs of CAM-related genes. Furthermore, AaPEPC1 overexpression enhanced proline biosynthesis, and improved salt and drought tolerance in the transgenic plants. Under salt and drought stress conditions, the dry weight of transgenic tobacco plants overexpressing AaPEPC1 was increased by up to 81.8% and 37.2%, respectively, in comparison with wild-type plants. Our findings open a new door to the simultaneous improvement of photosynthesis and stress tolerance in plants.

Antibacterial Activity and Phytochemical Components of Leaf Extracts of Agave americana

Background

Ethiopian flora is a source of innumerable cures for several infections. The medicinal potential of A. americana has been evaluated in some studies. The current study aimed to investigate the antimicrobial effect of A. americana leaf extracts on selected bacterial strains and to determine the phytochemical components.

Purpose

To determine the phytochemical constituents and in vitro antibacterial activity of leaf extracts of Agave americana against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella species, and Eshercia coli.

Methods

The macerated and Soxhlet crude extracts of Agave americana were further fractionated to petroleum ether, chloroform, acetone, and methanol fractions. The agar well diffusion method and disc diffusion methods were used to test the antibacterial effect and determine the minimum inhibitory concentration (MIC) of the plant extract. Standard methods of determination were used to determine the phytochemical components of Agave americana.

Results

The percentage yield of crude extracts of A. americana was 15.11%. Alkaloids, saponins, tannins, polyphenols, and flavonoids were identified as phytochemical constituents of A. americana. The crude and solvent fractions of A. americana have an antibacterial activity comparable to gentamycin, with zones of inhibition ranging from 17 to 40mm and minimum inhibitory concentration (MIC) of 2.5 mg mL for S. aureus, P. aeruginosa, and S. typhi strains and 10 mg mL for E. coli strains. S. aureus and E. coli were the most and least susceptible bacteria among the four bacterial test strains tested.

Conclusion

The crude and solvent fractions of A. americana have antibacterial activity against S. aureus, P. aeruginosa, and S. thyphi, comparable to gentamycin.

Toxicity of botanical extracts and their main constituents on the bees Partamona helleri and Apis mellifera

Africanized and wild bees are sensitive to synthetic insecticides, but may not be sensitive to botanical extracts. In this work, we evaluated the toxicity of botanical extracts with homemade preparations used in agroecological crops and their constituents on the bees Apis mellifera and Partamona helleri. Toxicity bioassays of adult bees were done by means of oral exposure and ingestion, using the insecticide imidacloprid as a positive control. Dietary consumption, respiration rate and bee flight were evaluated as sublethal parameters. Although some extracts were toxic to bees, survival was always higher compared to the results obtained with the imidacloprid, which was lethal to 100% of bees. In dietary consumption, P. helleri consumed less (5 mg/bee) in 3 h than A. mellifera (11 mg/bee), and P. helleri consumed less (7 mg/bee) in 24 h than A. mellifera (22 mg/bee). There was no difference in consumption of food containing plant extracts or food containing water only. We did not detect any adverse effects of the botanical extracts on bee respiration rates or flight. The major constituent of N. tabacum is nicotine (8.4-15.1%), in A. americana it is β-caryophyllene (11.3%), and in A. colubrina, lupeol (12.2%). Imidacloprid and nicotine were more toxic to bees (LC₅₀ ≤ 1.3 and LC₅₀ ≤ 44.3). Botanical extracts were selective to A. mellifera and the native bee P. helleri, and therefore, have the potential for ecofriendly pest control.

Ecological Distribution and Genetic Variations of Some <i>Aloe</i> Species in Taif, KSA

BACKGROUND AND OBJECTIVES

Aloe is a medicinally and economically important genus. Many Aloes seem an endangered species because of over-collection, destruction of plants and destroyed of natural habitats. The objectives of current study was to survey, collect and identification of some Aloe species and to analyze genetic variations between the collected Aloe species.

MATERIALS AND METHODS

Four Aloe species (A. armatissima, A. edentata, A. parvicoma and A. pseudorubroviolacea) and Agave americana (Asperagaceae) were used as plant materials for ecological and genetic studies. In RAPD and ISSR analysis 23 and 16 primers, respectively were screened.

RESULTS

Ecological study showed that the 4 species are endemic: 2 are endangered (A. edentata and A. parvicoma) and the others are not-endangered (A. armatissima and A. pseudorubroviolacea), while A. americana was introduced as ornamental species. Concerning RAPD, a total of 134 reproducible bands of them 131 bands are polymorphic ~ 97.65% polymorphism were produced, which ranged from 9 bands (primer OPC-04) to 18 (primer OPA-03) bands, with an average 13.4 bands/ primer, ranging from ~300-2500 bp. According to ISSR, 113 reproducible bands were totally yielded with an average 12.6 bands/primer, from ~180-1500 bp, of which 107 poly-morphic bands number (PBN) ~94.96% polymorphism ranged from 10 bands (primer UBC-818 and primer UBC-819) to 14 (primer UBC-814) with an average of 11.9 PB/primer.

CONCLUSION

The results revealed high genetic variations between 4 bands Aloe species and A. americana species, which will be in concern for improvement, breeding and conservation programs.

Anti-inflammatory Effect of an Extract of Agave americana on Experimental Animals

BACKGROUND

Medicinal plants have the potential treasure to treat medical conditions for a long time based on error and trial method. Agave americana has been known as century plant or American aloe. The leaves contain genins, saponins, steroidal flavonoids, isoflavones, and coumarins. It has long been used for anti-inflammatory effects.

OBJECTIVES

This study was designed to evaluate the anti-inflammatory activity of the extract of A. americana.

MATERIALS AND METHODS

A. americana leaves extract is collected and the extract is done by percolation method. Inflammation is induced in experimental animals' carrageenan-induced paw edema model and cotton pellet-induced granuloma model. The extract of A. americana and standard, aspirin and indomethacin are given orally for the anti-inflammatory effects. The anti-inflammatory effects were measured at regular intervals of time to see the percentage inhibition of paw edema and reduction of weight of granuloma with percentage protection to compare the effect of the extract with the control and standard.

RESULTS

The extract of A. americana showed improved in percentage inhibition of paw edema in graded doses of hydroalcoholic extract of A. americana (HEAA) as compared with control in carrageenan-induced paw edema model. The percentage inhibition of 400 mg/kg of HEAA at the 3^rd h is almost comparable with the standard, aspirin. On the other hand, graded doses (200 and 400 mg/kg) showed a highly significant reduction (P < 0.001) in the weights of granuloma in comparison with the control in cotton pellet-induced granuloma model. The percentage inhibition of weight of granuloma by 400 mg/kg of HEAA is quite comparable to the standard, Indomethacin.

CONCLUSION

Anti-inflammatory activity is seen with the graded dose of HEAA. The plant contains flavonoids and genins which have been shown to have anti-edematous effects in the acute phase of inflammation. Thus, the plant contributes to its anti-inflammatory activity. Thus, higher doses of A. americana leaves need to be used to have the better understanding of the mechanism of anti-inflammation.

SUMMARY

The hydroalcoholic extract from Agave americana (100, 200, and 400 mg/kg, HEAA) were studied in carrageenan-induced paw edema model and cotton pellet-induced granuloma model in Wistar rats. The plant contains flavonoids and genins which have been shown to have anti-edematous effects in the acute phase of inflammation. The results were good with the higher doses of 200 and 400 mg/kg of HEAA. Its in vivo anti-inflammatory activity is in good agreement with the traditional use of A. americana. Abbreviation Used: HEAA: Hydroalcoholic extract of Agave americana leaves; SEM: Standard error mean; ANOVA: Analysis of variance; n: Number; g: gram; w/w: weight by weight; h: hour; kg: kilogram; mg: milligram.

Protective effect of Agave americana Linn. leaf extract in acetic acid-induced ulcerative colitis in rats

Introduction:

Natural plants always provide core compounds for new drug development. In the present life and food style, inflammatory bowel disease has become common and needs a lead compound for its drug development.

Aim:

To evaluate the effect of Agave americana Linn. leaf extract in acetic acid-induced ulcerative colitis in rats based on its traditional anti-inflammatory use.

Materials and Methods:

Male Wistar rats were pretreated with A. americana leaf extract in the dose of 200 and 400 mg/kg p.o. daily for 7 days. On 8^th day, 2 ml of 4% v/v acetic acid in saline was instilled into rats’ rectum. Prednisolone was used as standard drug and it was administered on the day of acetic acid instillation and continued for 3 days. Extract treatment was continued till 11^th day. Body weight, ulcer score, colonic muscle contraction, antioxidant activity and histopathology were studied. Statistical analysis was performed using Parametric one-way analysis of variance followed by Tukey's posttest.

Results:

A. americana have retained total body weight significantly (P < 0.01) and decreased colon weight/length ratio. Extract have shown a significant decrease (P < 0.001) in ulcer scores, myeloperoxidase, lipid peroxidase activity. Further, extract have shown significant improvement in colonic muscle contraction, histopathology of colon etc., which is comparable with standard drug.

Conclusion:

A. americana possess protective effect against acetic acid-induced colitis in rats.

Effect of Agave americana and Agave salmiana Ripeness on Saponin Content from Aguamiel (Agave Sap)

Steroidal saponins have shown beneficial health effects. Agave spp. leaves and rhizomes are sources of these compounds, but their presence has not been reported in the aguamiel. Aguamiel is the sweet edible sap from mature agave, and its quality is influenced by the plant ripening stage. The purpose of this research was to identify and quantitate saponins in aguamiel from Agave americana and Agave salmiana at two ripening stages. Saponins and sapogenins were identified with HPLC/ESI-MS/TOF and quantitated with HPLC/ELSD. Results proved the presence of saponins derived from kammogenin, manogenin, gentrogenin, and hecogenin. The saponin content in aguamiel from immature A. salmiana was 2-fold higher (478.3 protodioscin equivalents (PE) μg/g aguamiel (DM)) compared with A. americana (179.0 PE μg/g aguamiel (DM)). In both species, saponin content decreased when plants reached sexual maturity. This should be considered before evaluating the effects of Agave spp. as a source of bioactive saponins.

In vitro cytotoxicity study of agave americana, strychnos nuxvomica and areca catechu extracts using mcf-7 cell line

Research is focusing on the search for new types of natural chemotherapeutic agent that is plant based medicines which are proving to be excellent sources of new compounds. In present research study, an attempt was made to prove cytotoxicity activity of various parts of medicinal plants such as Agave americana, Strychnos nuxvomica and Areca catechu using MCF-7 and Vero cell line. Various parts of the medicinal plants were extracted by soxhlet apparatus using solvents likes methanol and water. By trypan blue dye exclusion method, Viability of MCF-7 and Vero cell lines were 85.50 and 81.13%, respectively. IC(50) value of methanol extract of Agave americana leaves and aqueous extract of Areca catechu fruits were found to be 545.9 & 826.1 μg/ml by SRB assay and 775.1 & 1461pg/ml by MTT assay, respectively, against MCF-7 cell line. From cytotoxicity study data by SRB and MTT assay, it revealed that methanol extract of Agave americana and aqueous extract of Areca catechu are potent cytotoxic.