Mineral Fertilization Influences the Growth, Cryptolepine Yield, and Bioefficacy of Cryptolepis sanguinolenta (Lindl.) Schlt.

Jacqueline Naalamle Amissah,Ivan Addae-Mensah,Chris Mpere Asare,Benjamin Azu Okorley,Regina Appiah-Opong,Forgive Enyonam Alorvor,Dorcas Osei-Safo

doi:10.3390/plants11010122

Abstract

Cryptolepis sanguinolenta (Lindl.) Schlt., the main source of cryptolepine alkaloid, is intensively exploited in the wild to treat malaria and Lyme disease. In this study, the influence of four inorganic fertilizers (supplying N, P, K, or NPK) and four growth periods (3, 6, 9, and 12 months after transplanting) on the herb’s root biomass, cryptolepine content and yield, and biological activities were investigated in a pot and field trial. The results showed the application of N (in the form of Urea or NPK) increased root biomass yield, cryptolepine content, and cryptolepine yield compared to unfertilized plants. The 9-month-old plants recorded the maximum cryptolepine content (2.26 mg/100 mg dry root) and cryptolepine yield (304.08 mg/plant), indicating the perfect time to harvest the herb. Plant age at harvest had a more significant influence (50.6–55.7%) on cryptolepine production than fertilizer application (29.2–33.3%). Cryptolepine extracts from 9- to 12-month-old plants had the highest antiplasmodial activity (IC50 = 2.56–4.65 µg/mL) and drug selectivity index (2.15–3.91) against Plasmodium falciparum Dd2. These extracts were also cytotoxic to Jurkat leukaemia cell lines (CC50 < 62.56 µg/mL), indicating the possible use of cryptolepine for cancer management. Growing the herb in the field increased cryptolepine yield 2.5 times compared to growth in a pot, but this did not influence the antiplasmodial activity of the extract. Commercial cultivation of C. sanguinolenta for 9 months combined with N application could be a promising solution to the sustainable use of this threatened medicinal species.

Highlights

N was the most promising, the results showed that P application enhanced cryptolepine production relative to the unfertilized plants in the 9-month growth period
The study showed that mineral fertilization and plant age at harvest positively affect the cryptolepine yield in C. sanguinolenta
Field production of the herb improved cryptolepine yield better than production in pots, but this did not significantly change the antiplasmodial activity of cryptolepine extracts, which increased with ageing in the plants

Summary

Introduction

Cryptolepis sanguinolenta (Lindl.) Schlecter (family Periplocaceae) is among the indigenous herbal vines that have received much attention in West African traditional medicine. In Ghana, C. sanguinolenta is widely used in decoctions and powders to treat malaria, a deadly disease of concern for public health, especially in areas where orthodox medicines are not readily available [5,6]. It is being studied in clinical trials as a potential therapy for the novel coronavirus disease 2019

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Conclusion