Abstract
Haematostaphis barteri Hook.f. (Anacardiaceae) is widely used in African traditional medicine for the management of malaria and other ailments. However, its active antiplasmodial constituents remain insufficiently characterized. To evaluate the antiplasmodial and antioxidant activities of the stem bark extract of H. barteri , identify its major bioactive constituents, and explore their potential interactions with falcipain-2 through exploratory docking studies in order to better understand compounds that may contribute to its traditional medicinal use. A hydroethanolic stem bark extract was evaluated for in vitro antiplasmodial activity against Plasmodium falciparum Dd2 (multidrug-resistant) and 3D7 (chloroquine-sensitive) strains. The extract was fractionated by column chromatography into four fractions (A–D), which were similarly tested. Further chromatographic purification of fractions A, B, and C yielded six known compounds: 3- O -methylellagic acid-4′- O - α -rhamnopyranoside ( 1 ), stigmast-4-en-3,6-dione ( 2 ), stigmast-3,6-dione ( 3 ), β -sitosterol ( 4 ), 6-hydroxystigmast-4-en-3-one ( 5 ), and β -sitosterol-3-O- β -D-glucoside ( 6 ). Structures were elucidated using NMR and MS techniques. Exploratory molecular docking was conducted to investigate potential binding modes toward falcipain-2. Antioxidant activity was assessed using DPPH and FRAP assays, and isolated compounds were screened for antiplasmodial activity against both parasite strains. The crude extract exhibited good antiplasmodial activity with IC 50 values of 13.0 ± 2.0 μg/mL (PfDd2) and 8.6 ± 2.3 μg/mL (Pf3D7). Among the fractions, fraction C showed the highest activity (12.7 ± 0.2 μg/mL; 8.0 ± 1.5 μg/mL), followed by fraction B, A, and D. Six known compounds were isolated, with compounds 1 , 3 , and 5 reported for the first time in the Anacardiaceae family. Docking analysis yielded modest predicted binding energies (−5.4 to −6.8 kcal/mol) and did not show a clear correlation with experimental antiplasmodial activity, suggesting that strong falcipain-2 inhibition is unlikely to represent the primary mechanism of action. All samples demonstrated antioxidant activity, and compound 1 exhibited the strongest effect (DPPH IC 50 = 59.6 ± 10.4 μg/mL; FRAP IC 50 = 69.1 ± 0.2 μg/mL). In antiplasmodial assay, the isolated compounds exhibited weak to moderate activity, with compound 1 showing the lowest IC 50 values among them (31.6 ± 2.9 μM for PfDd2 and 22.1 ± 0.1 μM for Pf3D7). The findings provide preliminary pharmacological support for the traditional antimalarial use of H. barteri . In vitro assays indicate that several constituents may contribute to the observed inhibition of Plasmodium growth, with compound 1 showing moderate activity. Compounds 1 , 3 , and 5 were identified in the Anacardiaceae family for the first time, highlighting their potential as phytochemical markers. • Haematostaphis barteri stem-bark extract exhibited notable in vitro activity against P. falciparum Dd2 and 3D7. • Fractionation yielded six known compounds, three reported for the first time in Anacardiaceae. • 3- O -methylellagic acid-4′- O - α -rhamnopyranoside ( 1) showed the most favorable falcipain-2 docking score and the highest antioxidant activity among the isolated compounds. • Compound 1 exhibited the most potent antiplasmodial effect among all isolated constituents. • Findings support the traditional antimalarial use of H. barteri and identify compound 1 as a potential phytochemical marker contributing to the extract’s activity.
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Claims 15
Claim · model-written summary
The crude stem bark extract showed good in vitro antiplasmodial activity against P. falciparum Dd2, IC50 13.0 ± 2.0 μg/mL.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“The crude extract exhibited good antiplasmodial activity with IC 50 values of 13.0 ± 2.0 μg/mL (PfDd2) and 8.6 ± 2.3 μg/mL (Pf3D7)”
Claim · model-written summary
The crude stem bark extract showed good in vitro antiplasmodial activity against P. falciparum 3D7, IC50 8.6 ± 2.3 μg/mL.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“The crude extract exhibited good antiplasmodial activity with IC 50 values of 13.0 ± 2.0 μg/mL (PfDd2) and 8.6 ± 2.3 μg/mL (Pf3D7)”
Claim · model-written summary
Among the fractions, fraction C showed the highest antiplasmodial activity, followed by fractions B, A and D.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“Among the fractions, fraction C showed the highest activity (12.7 ± 0.2 μg/mL; 8.0 ± 1.5 μg/mL), followed by fraction B, A, and D”
Claim · model-written summary
Six known compounds were isolated from the stem bark extract.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“Six known compounds were isolated”
Claim · model-written summary
Compounds 1, 3 and 5 were reported for the first time in the Anacardiaceae family.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“compounds 1 , 3 , and 5 reported for the first time in the Anacardiaceae family”
Claim · model-written summary
Docking of the isolated compounds toward falcipain-2 yielded modest predicted binding energies of -5.4 to -6.8 kcal/mol.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“Docking analysis yielded modest predicted binding energies (−5.4 to −6.8 kcal/mol)”
Claim · model-written summary
Docking scores did not show a clear correlation with experimental antiplasmodial activity.
- Taxon
- Haematostaphis barterit0
- Organ / stage
- stem barkt0
- Gene
- falcipain-2e1
- Outcome
- experimental antiplasmodial activitye0
Not reportedDirection
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“did not show a clear correlation with experimental antiplasmodial activity”
e1“strong falcipain-2 inhibition is unlikely to represent the primary mechanism of action”
Claim · model-written summary
Strong falcipain-2 inhibition is unlikely to be the primary mechanism of the antiplasmodial action.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“strong falcipain-2 inhibition is unlikely to represent the primary mechanism of action”
Claim · model-written summary
Compound 1 showed the most favorable falcipain-2 docking score.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“showed the most favorable falcipain-2 docking score”
Claim · model-written summary
All samples demonstrated antioxidant activity.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“All samples demonstrated antioxidant activity”
Claim · model-written summary
Compound 1 showed the strongest antioxidant effect in the DPPH assay, IC50 59.6 ± 10.4 μg/mL.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“compound 1 exhibited the strongest effect (DPPH IC 50 = 59.6 ± 10.4 μg/mL; FRAP IC 50 = 69.1 ± 0.2 μg/mL)”
Claim · model-written summary
Compound 1 showed the strongest antioxidant effect in the FRAP assay, IC50 69.1 ± 0.2 μg/mL.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“compound 1 exhibited the strongest effect (DPPH IC 50 = 59.6 ± 10.4 μg/mL; FRAP IC 50 = 69.1 ± 0.2 μg/mL)”
Claim · model-written summary
The isolated compounds showed weak to moderate antiplasmodial activity.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“the isolated compounds exhibited weak to moderate activity”
Claim · model-written summary
Compound 1 had the lowest IC50 among the isolated compounds against PfDd2, 31.6 ± 2.9 μM.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“the isolated compounds exhibited weak to moderate activity, with compound 1 showing the lowest IC 50 values among them (31.6 ± 2.9 μM for PfDd2 and 22.1 ± 0.1 μM for Pf3D7)”
Claim · model-written summary
Compound 1 had the lowest IC50 among the isolated compounds against Pf3D7, 22.1 ± 0.1 μM.
Verbatim
t0“stem bark of Haematostaphis barteri Hook.f.”
e0“the isolated compounds exhibited weak to moderate activity, with compound 1 showing the lowest IC 50 values among them (31.6 ± 2.9 μM for PfDd2 and 22.1 ± 0.1 μM for Pf3D7)”