Phytochemical analysis and antioxidant activity of Haloxylon salicarnicum, Ochradenus arabicus and Tamarix nilotica

In the present investigation, the preliminary phytochemical analysis and antioxidant potential of hexane, chloroform, acetone and methanol extracts of Haloxylon salicarnicum, Ochradenus arabicus and Tamarix nilotica were reported. The presence of flavonoid, alkaloid, phenols, terpenoids, carbohydrate, tannin, protein, steroids, saponin, phlobatannin, cardiacglycoside, anthraquinines and volatile oils were determined and for antioxidant activity, DPPH, ABTS, superoxide anion radical and hydroxyl radical scavenging potential were studied. Strong presence of alkaloid, tannin, steroids in H. salicarnicum, flavonoid and phenols in O. arabicus and saponin T. nilotica were observed. In the present investigation, all the extracts inhibited the free radicals the methanol extract of O. arabicus was identified as potential crude extract compared to all other extracts with the IC50 values of 91.65 (DPPH), 94.62 (ABTS), 95.82 (O2) and 96.02 (OH) μg/mL. Whereas, the IC50 value of the standard, Gallic acid were 125.25 (DPPH), 142.32 (ABTS), 130.78 (O2) and 139.93 μg/mL (OH). Whereas, the IC50 value of the standard, Gallic acid were 125.25 (DPPH), 142.32 (ABTS), 130.78 (O2) and 139.93 μg/mL (OH)The present study suggests that methanol extract of O. arabicus can be used for the isolation potential natural antioxidant.


INTRODUCTION
Antioxidants are the compounds or materials which can effectively catch the free radicals and reduce the occurrence of damage induced by the oxidative stress. Now a day, antioxidants and free radicals are widely discussed in the in the nutritional and clinical field [1] since the free radicals induced oxidative stress is mainly associated with the number of human diseases. The risk of illness caused by the free radicals is mainly due to pollution, unhealthy life style, exposure to chemicals, smoking, drugs etc., [2][3]. Furthermore, antioxidants also play a vital role in food preservation through the oxidation inhibition process and contribution to health promotion rented by nutraceuticals and dietary supplements [4]. Lipid oxidation is a main factor destroying food quality of fruits and vegetables, meat [5] and dairy products [6] in the food industry [7,8].
The synthetic antioxidants such as butylated hydroxytanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate and citric acid are widely used in the food industry as preservatives /additives. Application of these antioxidants during food processing leads to the appearance of notable side effects [9] i.e., enlarge the liver size, increase the microsomal enzyme activity in living cells and can exhibit carcinogenic effects [10]. Hence, the researchers are focused on natural antioxidants found in plants, animals and microorganisms [4,11,12] and also strong chelators of metal ions [13]. So, the present investigation was aimed to investigate the preliminary phytochemical analysis and antioxidant potential of some UAE indigenous plants such as Haloxylon salicarnicum, Ochradenus arabicus and Tamarix nilotica.

Plant Collection and Crude Extract Preparation
The leaves of Haloxylon salicarnicum, Ochradenus arabicus and Tamarix nilotica were collected from its natural habitats in various palaces of Al Ain, UAE and the collected plants were dried in shade followed by oven (50 °C) prior to grinding in an electrical blender. For phytochemical analysis, methanol was used for the preparation of crude extracts. Whereas, for antioxidant study, different solvent systems viz. hexane, chloroform, acetone and methanol were used for preparation of crude extracts. After preparation, the solvents were evaporated and dried extracts were stored at 4 °C and used for antioxidant assay.

DPPH• radical scavenging activity
T h e D P P H s c a v e n g i n g a c t i v i t y w a s d e t e r m i n e d spectrophotometrically by the method of Brand-Williams et al. [16].

Hydroxyl radical (OH•) scavenging assay
The hydroxyl radical scavenging activity of the plants was evaluated by the method of Halliwell et al. [19].

Statistical Analysis
Statistical analysis was performed using one way analysis of variance followed by Duncan's Multiple Range Test using Statistical Package for the Social Science software (SPSS) package version 21.00. Results were expressed as mean±standard deviation for six replicates. P values < 0.05 were considered statistically significant.

Phytochemical Analysis
Preliminary phytochemicals analysis is a valuable step, in the detection of the bioactive compounds available in medicinal plants and subsequently may lead to drug discovery and development. The results on the preliminary phytochemical screening of H. salicarnicum, O. arabicus and T. nilotica are presented in Table

Antioxidant Activity
The results on percentage of DPPH•, ABTS• + , O 2 •− and OH • radicals inhibition are given in Figs. 1a-d (H. salicarnicum), 1e-h (O. arabicus) and 1i-l (T. nilotica) and the IC 50 values are presented in Table 2. All the extracts inhibited the free radicals in dose depended manner. In the present investigation, the  [25] reported the antioxidant potential of ethyl acetate, ethanol, and methanol extracts of Sargassum serratifolium. The authors found that ethanol was the efficient solvent for the extraction antioxidant molecule as the ethanol extract showed good antioxidant potential. Antioxidant activity of ethanol and water extracts of Trapa bispinosa leaves was studied by Xia et al. [26]. Ethanol extracts showed good stronger superoxide anion scavenging capacity potential. In that way, the

ACKNOWLEDGMENT
The Authors are grateful to Research Affairs, UAE University for financial support through SURE Plus Grand.