Gastroprotective, Antioxidant, Anti-Inflammatory, and Toxicological Evaluation of Stem Bark Extracts of Vitellaria paradoxa and Parkia biglobosa

Abstract

Background/Objectives: Oxidative stress is a pathophysiological factor that causes challenging issues in the treatment of several diseases, including gastric ulcer, inflammatory diseases, and adenocarcinomas. V. paradoxa and P. biglobosa are African plants whose parts are used for treating diseases, including gastrointestinal pathologies. This study aimed to characterize the gastroprotective, antioxidant, and anti-inflammatory activities of V. paradoxa and P. biglobosa stem bark extracts based on various solvents. Methods: The phytochemical screening and antioxidant evaluation were performed using radical scavenging (ABTS and DPPH) and reduction (FRAP and APM) methods. The anti-inflammatory activity was performed through an egg albumin denaturation model. The toxicological evaluation was performed on Artemia salina and female Wistar rat models, and the gastroprotective activity was carried out on an ethanolic-induced gastric ulcer rat model. Results: The results reported that V. paradoxa stem bark extracts contain catechin, epicatechin, ferulic acid, apigenin-7-gluc, and hesperidin, while P. biglobosa bark contains chlorogenic acid, catechin, caffeine, epicatechin, and cichoric acid. In the DPPH assay, the lowest scavenging capacities were 1.8 ± 0.21 mmol AAE/mg of dry extract (V. paradoxa, 97% ethanol) and 11.43 ± 0.208 mmol AAE/mg of dry extract (P. biglobosa, 50% ethanol). Similarly, for ABTS, the lowest scavenging capacities were 0.9726 ± 0.03952 mmol AAE/mg of dry extract (V. paradoxa, methanol with 1% HCl) and 1.3 mmol AAE/mg of dry extract (P. biglobosa, 97% ethanol), indicating strong antioxidant capacity. In the FRAP assay, both species reached a maximum reducing power of 2.39 mMol AAE/mg of dry extract (methanolic extract for V. paradoxa; methanol + 1% HCl for P. biglobosa). For APM, the 97% ethanolic extracts again showed the highest total antioxidant capacities: 31.78 ± 1.481 mMol AAE/mg (V. paradoxa) and 31.21 ± 0.852 mMol AAE/mg (P. biglobosa). The stem bark extracts of both V. paradoxa and P. biglobosa were revealed to be harmless in the Artemia salina as well as the rat model. The extracts of V. paradoxa as well as P. biglobosa exerted a stronger gastroprotective effect than omeprazole, a commonly used reference molecule. Conclusions: These extracts, rich in compounds exhibiting strong antioxidant, anti-inflammatory, and gastroprotective activities, surpassed omeprazole in ulcer protection in rat models. Their safety was confirmed in both Artemia salina and rodent assays. Future studies will explore their immunomodulatory, antiproliferative activities in vitro and in vivo and, specifically, the efficacy of isolated compounds in gastric adenocarcinoma models to assess these plants' anticancer potential and elucidate their underlying mechanisms.

Keywords: Parkia biglobosa extract; Vitellaria paradoxa extract; gastroprotection; oxidative stress; phytochemicals.

Figure 1

Total phenolic content (TPC) of stem bark of V. paradoxa (a) and P. biglobosa (b). Means with the same coefficients a, b, c, d and e are not statistically different.

Figure 2

Total flavonoid content (TFC) in the stem bark of V. paradoxa (a) and P. biglobosa (b). Means sharing the same letters a, b, c and d are not significantly different.

Figure 3

Total condensed tannins (TCT) in V. paradoxa (a) and P. biglobosa (b) stem bark extracts. Means sharing the same letters a, b, c or d are not statistically different.

Figure 4

Total hydrolyzable tannins (THT) content of V. paradoxa (a) and P. biglobosa (b) stem bark extracts. Means sharing the same letters a, b, c, d, e or f are not statistically different.

Figure 5

HPLC-DAD chromatograms of V. paradoxa stem bark extract: (a)—320 nm; (b)—285 nm; and (c)—267 nm.

Figure 6

HPLC-DAD chromatogram of P. biglobosa stem bark extract: (a)—267 nm; (b)—285 nm; (c)—320 nm; (d)—369 nm.

Figure 7

Molecular structure of phenolic compounds identified in the stem bark of V. paradoxa and P. biglobosa.

Figure 8

ABTS scavenging activity of V. paradoxa (a) and P. biglobosa (b) stem bark extracts. Means sharing the same coefficients a, b, or c are not statistically different.

Figure 9

DPPH scavenging activity of ethanolic extracts from V. paradoxa (a) and P. biglobosa (b) stem bark. Means with the same letters a, b, c or d are not statistically different.

Figure 10

Ferric reducing antioxidant power (FRAP) activity of V. paradoxa (a) and P. biglobosa (b) stem bark extract. Means sharing the same letters a, b, or c are not statistically different.

Figure 11

Phosphomolybdenum (APM) activity of ethanolic extract of V. paradoxa (a) and P. biglobosa (b) stem bark extract. Means with the same coefficients a, b, c, or d are not statistically different.

Figure 12

Protein denaturation inhibition activity of stem bark extract of V. paradoxa inhibition rate (a) and concentration for 50% inhibition (b). Means with the same coefficients a are not statistically different.

Figure 13

Protein denaturation inhibition activity of ethanolic extract of stem bark of P. biglobosa (a) concentration for 50% inhibition (b). Means with the same coefficients a, b, or c are not statistically different.

Figure 14

Correlation of pharmacological properties with phenolic content of V. paradoxa (a,b) stem bark extracts.

Figure 15

Correlation of pharmacological properties with phenolic content of P. biglobosa (a,b) stem bark extracts.

Figure 16

Cytotoxicity of V. paradoxa stem bark extracts on Artemia salina larvae: mortality (a); 50% mortality concentration (b). Means with the same coefficients a are not statistically different.

Figure 17

Cytotoxicity of P. biglobosa bark extracts on Artemia salina larvae: mortality (a); 50% mortality concentration (b). Means sharing the same coefficients a, b are not statistically different.

Figure 18

Changes in animal body weight during the 14-day follow-up of the acute toxicity test. Means sharing the same coefficients a are not statistically different.

Figure 19

Hematological parameters of animals subjected to the acute toxicity test: hematocrit (a), hemoglobin (b), red blood cell count (c), and white blood cell count (d). Means marked with the same coefficients a are not statistically different.

Figure 20

Immunological parameters of animals subjected to the acute toxicity test: lymphocytes (a), monocytes (b), eosinophils (c), and neutrophils (d). Means sharing the same letters a, b are not statistically different.

Figure 21

Liver function parameters of animals subjected to the acute toxicity test: AST (a); ALT (b). Means with the same letters a are not statistically different.

Figure 22

Kidney function parameters of animals subjected to the acute toxicity test: urea (a), creatinine (b). Means with the same coefficients a are not statistically different.

Figure 23

Correlation between hematological parameters, liver function, kidney function, and the different extracts: variables contribution (a), biplot (b).

Figure 24

Degree of protection of rat stomachs against ulceration (a); sample macroscopical observation on gastric tissues of the experimental rat (b): b₁: Vp97, b₂: Pb97, b₃: Vp50, b₄: Pb50, b₅: omeprazole, b₆: distilled water.

Figure 25

Total stomach acidity of gastric ulcer model rats treated with stem bark extracts of V. paradoxa and P. biglobosa. Means with the same coefficients a are not statistically different.

Figure 26

Correlation between total gastric acidity and protection rate against gastric ulcer: correlation (a), regression (b).

Figure 27

Animals’ acclimation.