Plant Collection for Phytochemicals Analysis

By Laiba Sarwar

There are many similarities between collecting plants for

herbarium making and collecting plants for phyto

chemical analysis

The major difference are in addition to making a voucher

specimen you must collect a large amount of material

from each species designated for the laboratory and that

this sample must be prepared in a way that alter as little as

possible the chemical composition of plants.

Selecting the locality, time of the day an population of plants

Criterion for selecting the species

• Do some background bibliographic research on the species focusing on their distribution, abundance and reproductive biology.•Ensure that the species you have selected are abundant in the collected sites.•Choose large and mature plants that can better withstand the impact of harvesting than small and immature one. • Consider whether or not the plant population will yield a sufficient quantity of material for analysis.

• Take all necessary measure to guarantee that species

can continue to produce new vegetative growth of

seeds after being harvested

• If you gather whole plant ensure that one plant

remain in each stand.

• while picking leaves from plant leave enough foliage

so that plant continue to grow and reproduce.

• on trees and shrubs harvest from side branches rather

than main trunk of branches

• Bark and roots harvested with special care.

•Many root like organs like rhizome, stolon, tubers, bulbs

are actually modifies stems. They often have buds for

reproduction.

• woody plants have complex root system and they can

survive if some roots are left intact.

•Individuals of same plants growing on different

localities may have striking different level of active

compounds.

•Also samples collected at different time of the day and

night and the season fluctuate in potency.

•Plants should not be attacked by bacteria, fungi or small

insect as they result in change in phytochemicals

composition like alkaloids and terpenoids will rise in such

cases.

•Always collect flower and fruits in voucher collection

that will help identification and keep record for future.

Collecting the plants

Generally for phyto-chemical analysis the bulk is collected as dry material is needed as fresh material contain 80-90% (leaves) or 30-40% of water in bark or stem

Preparing the plantOnce assembled the plants need to be cut into small pieces that could be easy for handling.

Preserving the plantsGenerally plants material are preserved in the laboratory by fresh, frozen, dried, preserved or extracted in alchol.Generally icebox is generally used.

•Pharmacologist accept the dried plants but generally during

drying chemical composition is effected. Effect varies from

compound to compound and objective of project

• ensure to cut plant into very small pieces to ensure uniform ad

rapid drying.

•Significance in case of drying in oven: ensure light heat and

slow drying.

•Generally het is kept below 50C.

•Two major Method of Drying •Sun Drying •Shade Drying (preferred method)

•Keep the field note book•How plant is preserved•Any specific env. condition•Maturity of plants•Time of day when collection has to made.

•Labeling the specimen

•Shipping the specimen

Ethics of Collecting

• Physical vouchers taken only where local population

suffers no irrevocable harm

• With rare species under investigation, essential study

materials should be removed judiciously, mitigating

damage to plant

• Required permits prior to collecting – OR authorized

personnel participate in collecting – OR authorized

personnel provide materials

• Permission from landowner or authorized personnel

Regulations on Collecting

•Heritage Programs (=endangered species bureaus) track rare

animals and plants

•Advisory committees of experts make biennial

recommendations to legislature for protection

• Special Concern (potentially imperiled), Threatened

(demonstrably imperiled) and Endangered (critically imperiled)

species receive attention

•Threatened and Endangered species cannot be taken on public

land without a permit

•Some states have “wildflower” laws trilliums, orchids‐‐

Regulations on Collecting

•Same are listed species, Threatened and Endangered species cannot be taken on public land without a permit•Those on private land also protected in theory •Taking for research purposes through application

International Collecting

•Primary set of voucher duplicates should go to in country ‐institution(s) •Most international permits require at least one complete set deposited at national institution•In country institution will often provide collecting ‐equipment, expertise •Customary for types of new organisms to be deposited at in country institutions (at least duplicates = isotypes)‐

International Collaboration

Involvement of in country personnel during collecting #‐Many international permits require in country assistant ‐(e.g., graduate student) as commitment to sharing of expertise Foreign researcher often expected to cover expenses of in‐country assistant – Staff of in country herbarium may often ‐“double” as field assistants, liaisons for permits, and tend to processing/mailing of vouchers after expedition

•Amount of material collected should not exceed 100-150gms unless permission granted.•In case of partnership with foreign countries 60% of the income arising from budget should be given to country organization•Country receives 51% of royality arising from external collaboration that result in marketable produtcs.•No country should give exclusive rights to the external parties.•Complete evaluation results should be supplies to the supplying country within 6-9 months•It there is chance of exploitation , cost of sustainable harvesting and alternative supplies must be borne of external organizations.•Contribution should be recognized through co-authorship•Where possible screening of the extracts should be carried out in country of origin