HEPATOPROTECTIVE ACTIVITY OF ISOQUINOLINE ALKALOIDS (F-5, F-24), AND THEIR DERIVATIVES (KV-6, KV-8)

Abstract. Experiments revealed that isoquinoline alkaloids F-5, F-24, and their derivatives (KV-6, KV-8) exhibit pronounced hepatoprotective activity in CCl₄-induced hepatotoxity model in mice. These compounds suppress the activity of ALT and AST enzymes during CCl₄-intoxication. Analysis of their effects showed that hepatoprotective activity increases in the following order: F-24<F-5<KV-8<KV-6. These results can be used as a scientific basis for the development of hepatoprotective agents based on isoquinoline alkaloids and their derivatives, depending on their chemical structure.

Keywords: isoquinoline alkaloids, ALT, AST, CCl₄-induced hepatotoxity, hepatoprotective effect.

According to World Health Organization statistics, 3 million people will die from liver disease by 2024, and this rapidly growing rate represents a serious medical, socioeconomic, and global problem. Developing new approaches to treating these diseases and creating effective next-generation pharmaceuticals is therefore crucial [Hu et al., 2025; Patel et al., 2025].

A number of studies have described in detail the origin of liver diseases, pathogenesis, and mechanisms of action of hepatoprotective agents. In particular, it was noted that the therapeutic effect of broad-spectrum hepatoprotectors (including polyphenolic compounds, flavonoids) includes stimulation of the antioxidant system of hepatocytes, antiradical activity (suppression of ROS formation), optimization of enzyme activity, etc. [Zhu et al., 2025].

The aim of this study was to compare the hepatoprotective activity of some isoquinoline alkaloids (F-5, F-24) and their derivatives (KV-6, KV-8) by their effect on transaminase enzymes – alanine aminotransferase (ALT) and aspartate aminotransferase (AST) – in the blood plasma of mice with experimental toxic hepatitis induced by CCl₄.

Research materials and methods

The experiments were conducted in 2023-2024 in the Metabolomics laboratory of the Institute of Biophysics and Biochemistry of the National University of Uzbekistan named after Mirzo Ulugbek. The objects of the study were white mice (♀/♂, m=20.5-26.2 g), which were fed standard food (water) under standard vivarium conditions (room temperature +20±5°C, relative air humidity 75±10%, light regime 12:12 hours). When working with experimental animals in scientific research, the requirements of the rules developed by the International Council for International Organizations of Medical Sciences (1985), the European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (Strasbourg, 1986), the Declaration developed by the European Union (86/609/EEC), and the Bioethical Statement of the Institute of Biophysics and Biochemistry of the National University of Uzbekistan (No. BRC/IBB; N44/2024/75-1) were observed. Isoquinoline alkaloids (F-5, F-24) and their derivatives with the flavonoid quercetin (KV-6, KV-8), provided by the staff of the S.Yu.Yunusov Institute of Plant Chemistry of the Academy of Sciences of the Republic of Uzbekistan were used as objects of research [Zhurakulov et al., 2015].

The hepatoprotective activity of isoquinoline alkaloids and their derivatives was assessed using a standard method on a model of experimental toxic hepatitis in mice caused by CCl₄ [Salim et al., 2025].

To create an experimental model of toxic hepatitis, we used white outbred mice of both sexes (♂♀, m=20.5-26.2 g) aged 2-3 months, kept in vivarium conditions on standard food and water. During the experiments, animals were administered intraperitoneal CCl₄ solution (diluted in olive oil) at a dose of 1 ml/kg for 14 days (on the 1^st, 5^th and 11^th days) [Rafiq et al., 2024].

The activity of ALT and AST (μkat/l) in the blood serum of mice was analyzed using a biochemical analysis reagent kit from Cupress Diagnostica (Belgium) and an Agilent Cary 60 Uv-Vis spectrophotometer (Agilent Technologies, USA) [Reitman and Frankel, 1957; Rafiq et al., 2024].

Mathematical and statistical processing of the obtained experimental results was carried out by standard methods using special software packages “Microsoft Excel 2007” (Microsoft, USA), OriginPro v. 8.5 SR1 (EULA, USA).

Results and discussion

In the control group, ALT activity averaged 1.05±0.02 and 0.94±0.01 μkat/l in males and females, respectively, and with CCl₄ intoxication, these indicators increased to 12.23±0.19 and 10.53±0.16 μkat/l, respectively. Isoquinoline alkaloids (F-5, F-24) and their derivatives (KV-6, KV-8) were found to cause concentration-dependent (25-100 mg/kg) inhibition of ALT activity under CCl₄ intoxication conditions. It was established that the isoquinoline alkaloid F-5 at a maximum concentration of 100 mg/kg reduced ALT activity in male and female mice during CCl₄ intoxication to 8.19±0.14 and 7.14±0.25 μkat/l, respectively. It was also noted that the isoquinoline alkaloid F-24 at a maximum concentration of 100 mg/kg reduced ALT activity in experimental toxic hepatitis caused by CCl₄ to 9.43±0.18 and 8.45±0.26 μkat/l in male and female mice, respectively. 

It was found that the KV-6 at a maximum concentration of 100 mg/kg reduced the activity of ALT in experimental toxic hepatitis CCl₄ in male and female mice to 5.10±0.17 and 4.04±0.23 μkat/l, respectively, while the KV-8 (100 mg/kg) had this indicator of 7.13±0.28 and 6.05±0.15 μkat/l, respectively. It was also established that isoquinoline alkaloids (F-5, F-24), and their derivatives (KV-6, KV-8) inhibit AST activity depending on the concentration (25-100 mg/kg) under conditions of CCl₄-intoxication. It was noted that the isoquinoline alkaloid F-5 at a maximum concentration of 100 mg/kg reduced AST activity in male and female mice under CCl₄-intoxication to 10.35±0.27 and 12.64±0.32 μkat/l, respectively. For the isoquinoline alkaloid F-24 (100 mg/kg), a decrease in the value of this indicator was noted to 13.43±0.16 and 15.82±0.29 μkat/l, respectively. It was found that the KV-6 at a maximum concentration of 100 mg/kg reduced ALT activity in male and female mice poisoned with CCl₄ to 7.56±0.35 and 8.42±0.29 μkat/l, respectively, while the KV-8 (100 mg/kg) had this indicator down to 8.37±0.21 and 9.68±0.16 μkat/l, respectively.

At the next stage of the experiments, based on the data on the activity of ALT and AST, the values ​​of the coefficient of hepatoprotective action of isoquinoline alkaloids (F-5, F-24) and their derivatives (KV-6, KV-8) were calculated. Based on the analysis of the values ​​of the analyzed parameters under control conditions, CCl₄-induced hepatotoxity and the action of isoquinoline alkaloids (F-5, F-24) and their derivatives (KV-6, KV-8) at a concentration of 100 mg/kg, it was established that the coefficient of the hepatoprotective action of these substances has a characteristic increase in the series F-24<F-5<KV-8<KV-6. The maximum coefficient of hepatoprotective action was noted in the KV-6 (100 mg/kg), while it was established that the values ​​of ALT (μkat/l), AST (μkat/l) in the blood serum of mice amounted to 64, 72, 82, 67, 73% of the values ​​of CCl₄-induced hepatotoxity in males and females, respectively.

Conclusions

Thus, during the experiments it was established that the ALT activity in the control group of male and female mice was 1.05±0.02 and 0.94±0.01 μkat/l, respectively, and with CCl₄-intoxication it increased to 12.23±0.19 and 10.53±0.16 μkat/l. It was found that isoquinoline alkaloids F-5 and F-24 (25-100 mg/kg) significantly reduce the activity of ALT and AST during CCl₄-intoxication, with F-5 (100 mg/kg) reducing ALT activity to 8.19±0.14 μkat/l in males and 7.14±0.25 μkat/l in females, while for alkaloid F-24 these values ​​are 9.43±0.18 and 8.45±0.26 μkat/l, respectively. It has been confirmed that derivatives of isoquinoline alkaloids F-5 and F-24 (KV-6, KV-8) have a more pronounced hepatoprotective effect than the alkaloids, with KV-6 reducing ALT activity in male mice by 5.10±0.17 and in females by 4.04±0.23 μkat/l, while for KV-8 these values ​​are 7.13±0.28 and 6.05±0.15 μkat/l, respectively. Based on the analysis of the coefficient of hepatoprotective action, it was established that hepatoprotective activity increases in the series F-24<F-5<KV-8<KV-6.

The obtained results can be used as a scientific basis for the development of hepatoprotective agents depending on the chemical structure based on isoquinoline alkaloids and their derivatives.