than the remaining triterpenoids (IC 50 = 10–41 µM). However, for chymotrypsin
inhibition, a-amyrin linoleate (216) exhibited the potential activities of 16 µM with
a K i value of 27.5 µM. Further, these compounds have inhibited the enzymes
through non-competitive inhibition kinetics.
14.3.4.4 Anti-inflammatory Activity
Okoye et al. isolated 37 and 55 from the methanolic extract of A. boonei stem bark
(Okoye et al. 2014). The anti-inflammatory activity was evaluated by using egg
albumen-induced paw edema and xylene-induced ear edema models in rats. Apart
from this, gastric ulcerogenic, in vivo leukocyte migration, and RBC membrane
stabilization tests were also investigated. Prior (30 min) to the sub-plantar injection
of the egg albumen (0.1 mL), 37 (50 and 100 mg/kg) was administered orally.
Aspirin (100 mg/kg) was used as a positive control. Aspirin recorded significant
reduction in paw edema from the 2nd h, while the screened compound (100 mg/kg)
showed a significant activity from the 5th h. Ulcerogenic effect of 37 (50 and
100 mg/kg) was identified by using an ulcer index value. Indomethacin (40 mg/kg)
was administered as a positive control. Indomethacin evoked significant irritation of
the gastric mucosa compared with the control, while the test compound did not
evoke significant irritation. Heat-induced hemolysis and hypotonicity induced
hemolysis methods were used for the assessment of membrane stabilization
potential of 55 and 37. Diclofenac sodium (100 µg/mL) was used as a positive
control. Screened compounds (50 and 100 µg/mL) exhibited higher inhibition on
heat-induced haemolysis than diclofenac sodium (40% inhibition). Conversely, in
hypotonicity induced haemolysis, diclofenac sodium (50% inhibition) exhibited a
higher potential than the compounds. Further, to evaluate the acute topical
inflammation, the effects of 37 and 55 in xylene-induced ear inflammation were
determined. Compound 37 exhibited a higher % inhibition (>45% at 50 and
100 µg/mL) while 55 exhibited a comparable activity to that of indomethacin (45%
inhibition 100 µg/mL). Furthermore, a significant inhibition of leukocyte migration
and neutrophil infiltration were produced by 37 (100 mg/kg) in comparison with
positive control (indomethacin—50 mg/kg).
14.3.4.5 Antibacterial and Antioxidant Activities
Okoye et al. isolated eight flavonoid glycosides (219–226, Fig. 14.43) from the
methanolic extract of A. boonei leaves and evaluated the antioxidant activity (DPPH
free radical scavenging model) and antimicrobial activity (Agar well diffusion
technique) (Okoye and Okoye 2016). In DPPH scavenging assay, kaempferol
derivatives did not exhibit any kind of activities, while the quercetin derivatives
exhibited dose-dependent activities (IC 50 ) ranging from 36.0 to 66.0 µg/mL.
Quercetin-3-O-[a-L-rhamnopyranosyl (1 ! 4)-b-D-glucopyranoside] 223) and
Quercetin-3-O-robinobioside (220) exhibited a higher DPPH scavenging potential
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A. T. Paul et al.
inhibition, a-amyrin linoleate (216) exhibited the potential activities of 16 µM with
a K i value of 27.5 µM. Further, these compounds have inhibited the enzymes
through non-competitive inhibition kinetics.
14.3.4.4 Anti-inflammatory Activity
Okoye et al. isolated 37 and 55 from the methanolic extract of A. boonei stem bark
(Okoye et al. 2014). The anti-inflammatory activity was evaluated by using egg
albumen-induced paw edema and xylene-induced ear edema models in rats. Apart
from this, gastric ulcerogenic, in vivo leukocyte migration, and RBC membrane
stabilization tests were also investigated. Prior (30 min) to the sub-plantar injection
of the egg albumen (0.1 mL), 37 (50 and 100 mg/kg) was administered orally.
Aspirin (100 mg/kg) was used as a positive control. Aspirin recorded significant
reduction in paw edema from the 2nd h, while the screened compound (100 mg/kg)
showed a significant activity from the 5th h. Ulcerogenic effect of 37 (50 and
100 mg/kg) was identified by using an ulcer index value. Indomethacin (40 mg/kg)
was administered as a positive control. Indomethacin evoked significant irritation of
the gastric mucosa compared with the control, while the test compound did not
evoke significant irritation. Heat-induced hemolysis and hypotonicity induced
hemolysis methods were used for the assessment of membrane stabilization
potential of 55 and 37. Diclofenac sodium (100 µg/mL) was used as a positive
control. Screened compounds (50 and 100 µg/mL) exhibited higher inhibition on
heat-induced haemolysis than diclofenac sodium (40% inhibition). Conversely, in
hypotonicity induced haemolysis, diclofenac sodium (50% inhibition) exhibited a
higher potential than the compounds. Further, to evaluate the acute topical
inflammation, the effects of 37 and 55 in xylene-induced ear inflammation were
determined. Compound 37 exhibited a higher % inhibition (>45% at 50 and
100 µg/mL) while 55 exhibited a comparable activity to that of indomethacin (45%
inhibition 100 µg/mL). Furthermore, a significant inhibition of leukocyte migration
and neutrophil infiltration were produced by 37 (100 mg/kg) in comparison with
positive control (indomethacin—50 mg/kg).
14.3.4.5 Antibacterial and Antioxidant Activities
Okoye et al. isolated eight flavonoid glycosides (219–226, Fig. 14.43) from the
methanolic extract of A. boonei leaves and evaluated the antioxidant activity (DPPH
free radical scavenging model) and antimicrobial activity (Agar well diffusion
technique) (Okoye and Okoye 2016). In DPPH scavenging assay, kaempferol
derivatives did not exhibit any kind of activities, while the quercetin derivatives
exhibited dose-dependent activities (IC 50 ) ranging from 36.0 to 66.0 µg/mL.
Quercetin-3-O-[a-L-rhamnopyranosyl (1 ! 4)-b-D-glucopyranoside] 223) and
Quercetin-3-O-robinobioside (220) exhibited a higher DPPH scavenging potential
504
A. T. Paul et al.