Abstract
Background:
Asthma continues to rise globally, necessitating the exploration of alternative and complementary therapies, including combination treatments. Natural products and amino acids, such as C. esculentus (tiger nut) and L-arginine, may influence nitric oxide (NO) pathways involved in airway function.

Aim:
This study aimed to evaluate the effects of the combined administration of Cyperus esculentus aqueous extract and L-arginine on nitric oxide levels and selected hematological parameters in an ovalbumin-induced asthma model.

Methods:
A total of 48 Wistar rats (150–250 g) were divided into six groups (n = 8): control, asthma control, asthma + salbutamol (0.5 mg/kg), asthma + L-arginine (10 mg/kg), asthma + Cyperus esculentus (600 mg/kg), and asthma + combination treatment. Following ovalbumin (OVA) sensitization/challenge (except control), treatments were administered orally once daily for 28 days. The sex of the animals was not reported in the available study records; therefore, sex-dependent effects were not analyzed. At the end of the experiment, serum nitric oxide, red blood cell count, packed cell volume, hemoglobin, total protein, albumin, and polymorphonuclear cell measurements were analyzed using one-way analysis of variance followed by Tukey’s post hoc test (P < 0.05).

Results:
The untreated asthma group had lower serum NO equivalents and a higher polymorphonuclear cell count than the non-asthmatic control (P < 0.05), providing evidence of an OVA-associated systemic inflammatory response. Each treatment group had higher serum NO equivalents than the untreated asthma group (P < 0.05). The combination mean (53.07 ± 3.48 µmol/L) was numerically higher than the L-arginine (44.46 ± 3.93 µmol/L) and C. esculentus (44.42 ± 3.90 µmol/L) means; however, the study did not report inferential comparisons of the combination against each monotherapy and did not test an interaction model. The total protein, albumin, and RBC count did not differ significantly across the groups, whereas the PCV and hemoglobin were lower in the C. esculentus and combination groups than in the control (P < 0.05).

Conclusion:
L-arginine, C. esculentus, and their combination increased systemic serum NO equivalents relative to untreated OVA-challenged rats. These preliminary findings do not establish airway-specific efficacy, interaction mechanism, or synergy.

Key words: Asthma; Cyperus esculentus; L-arginine; Nitric oxide; Ovalbumin-induced Asthma Model.