Evaluation of Oil Components of Annona squamosa (Gishta) and Vangueria madagascariensis (Kirkir) Seeds and Antioxidant Activity of their Methanolic Extracts

Abstract

Seeds from Gishta (Annona squamosa) and Kirkir (Vangueria madagascariensis) were obtained from Khartoum central market and Alfola Agricultural Area, Kordofan State respectively and were investigated for their chemical composition such as moisture, oil, protein, fiber, ash, and carbohydrate. The seed oil was extracted by two methods (soxhlet and cold xv press), to show their effect on oil characteristics. Tocopherol, sterol and fatty acids composition were also investigated .The results of this work indicated an oil content of 26.8%, 40.0% and protein content of 17.5 %, 22.2,% of Gishta and Kirkir seed, respectively.The results showed that physicochemical properties of the two oils were in good agreement to those of conventional oils. Annona squamosa seed oil extracted with soxhlet xvi (ASSE) and cold press (ASCE), Vangueria madagascariensis seed oil extracted with soxhlet (VMSE) and cold press (VMCE) were found to contain high levels of unsaturated fatty acids, especially oleic 49.2, 50.5, 10.5, 10.4% and linoleic 22.3, 22.7, 63.1, 63.4% respectively. The dominant saturated fatty acids were palmitic 15.6 and 15.2% in ASSE and ASCE, respectively and 9.7 and 9.8%, in VMCE and VMSE, respectively. While xvii stearic was 10.6 and 9.3% in ASSE and ASCE, respectively, and 5.1 and 5.4%, in VMCE and VMSE, respectively The predominant tocopherols were found to be alpha-tocopherol 4.9, 4.4, 31.6 and 28.5mg/100 g in ASCE, ASSE, VMCE and VMSE, respectively, delta-tocopherol 11.7, 11.0, 8.4 and 10.5 mg/100g, respectively. Sterols profile shows that the major components are β- xviii sitosterol 45.24%, 45.48%, campesterol 24.66%, 22.65% and stigmasterol 21.86%, 20.08% in ASCE and VMCE oil, respectively.The total amount of amino acids were found to be 7.266 and 14.202 g/100g protein in Gishta and kirkir seeds, respectively. The total amount of the essential amino acids found in Gishta and Kirkir seeds were 4.302 and 8.319 g/100 proteins, respectively, and were significantly different (p<0.05). Oxidative Stability of xix the two oils extracted with the two methods were determined during storage at 70oC by measuring the peroxide value A squamosa seed oil was presented the highest oxidative stability. The total phenolic compounds and total flavonoids were investigated beside the potential antioxidant activity of Annona squamosa and V. madagascariensis methanolic extracts. The content of total phenolics in the xx extracts was determined spectrometrically according to the Folin-Ciocalteu procedure. The results indicated high phenolic content for Gishta roots, bark and Kirkir leaves, bark extracts. Also high flavoniod content was determined in leaves extracts of the two plants. The antioxidant activity by DPPH and ORAC of extracts from Annona squamosa leaves (ASL), seed cake (ASC), bark (ASB) and root (ASR), Vangueria madagascariensis leaves (VML), xxi seed cake (VMC), and bark (VMB) was evaluated. The effect of Annona squamosa and Vangueria madagascariensis extracts on the oxidative stability of sunflower oil stored in the dark at 70°C were evaluated in comparison with the control and BHT (butylated hydroxytoluene) by measuring the formation of peroxide value and C D at 70°C for 72 hours. Plants extracts Gishta and Kirkir leaves (500 mg) effectively inhibited the xxii formation of peroxides in sunflower oil and showed the highest oxidative stability compared with 20 mg of BHT resulting in lower PVs and less C D. MTT assay was used to evaluate the cytotoxic activity of extracts from different parts of A. squamosa, and V. madagascariensis. Only ASL and VML were found effective. xxiii