Table 2.

Ethnopharmacological/traditional approach versus random screening approach of plant selection.

	Ethnopharmacological/Traditional Approach	Random Selection Approach
Characteristics	-Traditional or ethnopharmacological knowledge/application is the basis for plant candidate selection and pharmacological assay. It involves the observation, description and experimental analysis of traditionally used plant materials. -The traditional system of medicine, such as TCM and Ayurveda, possess well established written knowledge about medicinal plants and regularly revised. -The ethnopharmacological knowledge is easily accessible.	-Plant candidates for natural product discovery are randomly selected, mainly based on their availability.
Strengths	-Comparatively higher success rate. -Based on scientific disciplines including chemistry, botany, pharmacology, biochemistry, history, anthropology et.	-Extremely advantageous, when plant species from a region of high biodiversity has to be screened. -The selected samples has the potential of identification of unexpected biological activities and novel structures. -Can be applied for both general and focused pharmacological screening.
Weaknesses/Challenges	-Permits are needed for the collection and investigation of plant candidate; even may provoke legal-issues with the ethical groups or the country in which the traditional knowledge was originated, -Traditional systems such as Ayurveda and TCM use multicomponent mixtures as formulation and the identification of active constituents out of these mixtures are complicated due to complexity and synergistic effects -The concept of health and disease in traditional medicine widely deviate the modern concepts. For example TCM is highly influenced by Chinese philosophy. This may complicate the correct interpretation of the ethnopharmacological information. -Holistic and personalized approaches of these systems are difficult to access by current bioassay methods.	-Lower rate of success in comparison to ethnophramcological approach. -Flawed in the sense that there is no idea of bioactivity. -The pharmacololgical screening used for randomly selected samples are of small or medium throughput and the test samples (extracts, fractions or pure constituents) availability is low limiting the number of bioassays that can be done.
Examples	-Galegine isolated from Galega officinallis L. inspired the synthesis of metformin and other biguanidines antidiabetics; papaverine from Papaver somniferum L.; quinine from Peruvian Cinchona bark inspired the synthesis of chloroquine and mefloquine [20,48]; artemisinine from TCM herb A. annua led to the development of artemether [49]; andrographolide from Andrographis paniculata; Berbarine from Berberis aristata etc [18].	35,000 plant species screened through random selection between 1960 to 1980 leading to discovery of paclitaxel and camptothecin [18].