Moringa (Moringa oleifera), belongs to the family Moringaceae, a small group of species of the order of Brassicales that includes cabbage and radish (^{Olson, 2002})). The leaf has attracted the attention of the general public due to the nutritional and medicinal properties attributed to it. From the nutritional point of view, the moringa leaf has a high protein content (30%) and has anti-inflammatory effects (^{Tangestani et al., 2015})) and is a protective hepate (^{Fakurazi et al., 2012})), among others effects. One of the possible reasons why this plant has these properties is the presence of flavonoids, vitamins and carotenoids, among other secondary metabolites it contains (^{Guzmán-Maldonado et al., 2015})).

Due to the boom that the moringa leaf has acquired, its production has increased significantly. Harvesting of the leaf is carried out without taking into account the possible variation in the chemical composition and biological activity of mixtures of leaves with different origin. The objective of the present work was to explore the possible variation in the phenolic composition and the antioxidant capacity of collections in the state of Chiapas. The means comparison was performed by the Tukey method (p< 0.05) using an ANOVA variance analysis and Fisher’s of LSD method to create confidence intervals to generate the least significant difference (DMS) (p< 0.05).

In all cases, the average is the average of three replicates. The leaves of 20 different trees were harvested from the moringa orchard of the Experimental Field of Izapa Chiapas-INIFAP. Each of the trees was collected from different localities of the state and planted with the intention of maintaining a representative collection of the species. The content of total phenols (^{Singlenton et al., 1999})), condensed tannins (^{Deshpande and Cheryan, 1985})), simple phenolics by (HPLC) (^{Ramamurthy et al., 1992})) and antioxidant capacity against oxygen radicals (ORAC) (^{Ou et al., 2001})) and against positive radicals (ABTS+) (TEAC) (^{Van den Berg et al., 1999})).

The range in total phenol content ranged from 2 436.3 to 3 749.9 mg EAG/100 g while that of condensed tannins was 3.04 to 39.57 mg EC/100 g (Table 1)). In both cases, the minimum significant difference (DMS) was 202.2 for total phenols and 4.8 for condensed tannins; it is obvious that there is greater variability in the collections in the content of condensed tannins and therefore the mixtures will present a greater variation in these compounds. However, the level of condensed tannins is very low in comparison with other species and therefore, a possible anti-nutrimental effect of tannins can be ruled out as they have the property of decreasing the bioavailability of minerals and proteins.

EAG= equivalentes de ácido gálico; EC= equivalentes de catequina; DMS= fenoles totales= 202.2; taninos condensados= 4.8.

Table 1 Content of total phenols and condensed tannins in the moringa collection leaf from the state of Chiapas. 

It has been reported in beans that levels above 2000 mg EC/100 g have a negative effect on the development of laboratory rats (^{Reynoso et al., 2007})). On the other hand, 13 of 20 collections have a high content of total phenols which can be reflected in a high antioxidant capacity.

Four simple phenolic compounds were identified: gallic acid, rutin, chlorogenic acid and cumaric acid in the leaves of the moringa collection (Table 2)); however, coumaric acid was only present in 25% of the samples, but with a wide range in its content from 89.3 to 805.2 mg/100 g. A similar situation was observed with rutin (83.3-1948.7 mg/100 g), gallic acid (24.08-110.22 mg/100 g) and chlorogenic acid (97-1315.2 mg/10 g).

Promedios con letras similares en la misma columna son estadísticamente iguales (Tukey, 0.05).

Table 2 Contents of simple phenolic compounds (mg/100 g, bs) in the moringa collection leaf from Chiapas.  

The levels in the antioxidant capacity of the collections presented a lower range (402.53-559.39 μmol ET/g) for ORAC than for TEAC (389.3-587.72 μmol ET/g) (Table 3)). This high variation allows predicting that leaf blends of this species will exhibit poor uniformity in the phenolic compounds content and antioxidant capacity.

ET = Equivalentes de Trolox; DMS: ORAC= 77.7; TEAC= 65.8.

Table 3 Antioxidant capacity of leaf extracts from moringa collections from the state of Chiapas.