Dragon's Blood Sap: Storage Stability and Antioxidant Activity

Abstract

Currently, consumers are demanding additive-free, fresher, and more-natural products. Dragon's Blood Sap (DBS), the deep red latex of the specie of tree Croton lechleri (Müll. Arg.), contains a high concentration of phenolic compounds of great interest for the food, pharmaceutical, and cosmetic industries. These chemical compounds are highly susceptible to degradation. Therefore, DBS storage stability and its photo-oxidation was studied by Fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectrophotometry for 39 days at different temperatures (4⁻21 °C) and relative humidities (0⁻56%), as well as under UV light exposure. It was observed that the degradation of phenolic compounds was reduced at 0% relative humidity (RH), not showing a significant effect of temperature in the range studied. UV light irradiation degraded DBS in a 20%. DBS has an exceptional high and stable antioxidant content (≥93% inhibition percentage of DPPH), which makes it a unique property to consider the DBS as an antioxidant agent or ingredient for consumer products formulations.

Keywords: Dragon’s Blood Sap; FT-IR; UV-Vis spectrophotometry; antioxidant activity; proanthocyanidins; storage stability.

Figure 1

UV-Vis spectrophotometry screening spectra of Dragon’s Blood Sap (DBS) at a concentration of 0.5 mg/mL.

Figure 2

Evolution of the DBS concentration under various % relative humidity (RH) and ambient temperature (~21 °C) after 39 days of storage according to the different absorption bands at 331 nm (A), at 347 nm; (B) at 464 nm; (C) and at 579 nm (D). Different letters within the graph (a–b) indicate significant differences among the conditions (p < 0.05). Different letters within the graph (ab, bc) indicate no differences among the samples (p > 0.05).

Figure 2

Evolution of the DBS concentration under various % relative humidity (RH) and ambient temperature (~21 °C) after 39 days of storage according to the different absorption bands at 331 nm (A), at 347 nm; (B) at 464 nm; (C) and at 579 nm (D). Different letters within the graph (a–b) indicate significant differences among the conditions (p < 0.05). Different letters within the graph (ab, bc) indicate no differences among the samples (p > 0.05).

Figure 3

Tukey’s honestly significant difference (HSD) test of the evolution of Dragon’s Blood Sap concentration after 39 days of storage at 21 °C and different relative humidity. Different letters within the graph (a–b) indicate significant differences among the conditions (p < 0.05). The ab value indicates no differences among the conditions (p > 0.05).

Figure 4

Evolution of DBS concentration after 39 days of storage under low (4 °C) and ambient temperature (~21 °C) and 0% RH, according to the different absorption bands: (A) 331 nm; (B) 347 nm; (C) 464 nm; (D) 579 nm. Different letters indicate significant differences among the samples (p < 0.05).

Figure 4

Evolution of DBS concentration after 39 days of storage under low (4 °C) and ambient temperature (~21 °C) and 0% RH, according to the different absorption bands: (A) 331 nm; (B) 347 nm; (C) 464 nm; (D) 579 nm. Different letters indicate significant differences among the samples (p < 0.05).

Figure 4

Evolution of DBS concentration after 39 days of storage under low (4 °C) and ambient temperature (~21 °C) and 0% RH, according to the different absorption bands: (A) 331 nm; (B) 347 nm; (C) 464 nm; (D) 579 nm. Different letters indicate significant differences among the samples (p < 0.05).

Figure 5

Tukey’s test of the evolution of Dragon’s Blood Sap concentration at different storage temperatures and 0% RH. Different letters indicate significant differences among the samples (p < 0.05).

Figure 6

Evolution of DBS concentration after 39 days of storage under UV-light according to the different absorption bands: 331 nm; 347 nm; 464 nm; 579 nm. Different letters indicate significant differences among the samples (p < 0.05). Different letters within the graph (abc, bc) indicate no differences among the samples (p > 0.05).

Figure 7

Typical Fourier transform infrared spectroscopy (FT-IR) spectrum of freeze-dried DBS. Arrows indicates the Functional Groups bands discussed in the text.

Figure 8

Evolution of the decay percentage of DBS characteristic functional groups with respect to the internal standard band at 1519 cm⁻¹ after 39 days under different temperatures, % RH, and UV-light irradiation: (A) Hydroxyl group (-OH) (3300 cm⁻¹); (B) carbonyl group (C=O) (1715 cm⁻¹); (C) alkenyl group (C=C) (1610 cm⁻¹); (D) methylene group (C–H₂) (1440 cm⁻¹); and (E) methyl group (C–H₃) (1342 cm⁻¹).

Figure 8

Evolution of the decay percentage of DBS characteristic functional groups with respect to the internal standard band at 1519 cm⁻¹ after 39 days under different temperatures, % RH, and UV-light irradiation: (A) Hydroxyl group (-OH) (3300 cm⁻¹); (B) carbonyl group (C=O) (1715 cm⁻¹); (C) alkenyl group (C=C) (1610 cm⁻¹); (D) methylene group (C–H₂) (1440 cm⁻¹); and (E) methyl group (C–H₃) (1342 cm⁻¹).

Figure 8

Evolution of the decay percentage of DBS characteristic functional groups with respect to the internal standard band at 1519 cm⁻¹ after 39 days under different temperatures, % RH, and UV-light irradiation: (A) Hydroxyl group (-OH) (3300 cm⁻¹); (B) carbonyl group (C=O) (1715 cm⁻¹); (C) alkenyl group (C=C) (1610 cm⁻¹); (D) methylene group (C–H₂) (1440 cm⁻¹); and (E) methyl group (C–H₃) (1342 cm⁻¹).