Source(s) for Indole(s)...

[carcrash]

From the label of one hydroponics rooting agent.
Contains 0.55 percent Indole-3 Butyric Acid
About 12 grams with perfect extraction from an 8 oz container.

Essential Jasmine Oil % unknown
Alcohol: benzyl acetate benxyl alcohol 
Ester: benzyl benzoate - Ketone: cis-jasmone
Phenol: eugenol 
Ester: indole, methyl anthranilate, methyl jasmonate
nitrogen compounds (>1.5%): methyl anthranilate, indole

From a nutrient supplement capsule $22 per bottle 60 capsules
Indole 3-carbinol 200 mg
Other ingredients: Rice bran, Geletain, Water and Titanium Dioxide

Indigo Dye all Natural $36-50 a pound
I know the dye has been covered but not sure if this price makes this more feasable. Could not find a bulk price on 10 pounds to 1 ton.

Not a chemist I just follow the directions on the box mix

[odin]

Today, i have read that Jasmine flower contains indole, but i think that percentage is very low.

[carcrash]

I have been able to find yohimbine extract 8 percent and believe it can be found at up to 20 percent. Yohimbine is an indole alkaloid.

The trunk bark of yohimbe contains up to 6% indole alkaloids, mostly of the yohimbane class, including yohimbine, a-yohimbine, d-yohimbine, allo-yohimbine, coryantheine, etc. – plus various isomers and heteroyohimbanes. The best-researched alkaloid is yohimbine (17 a-hydroxy-yohimban-16a-carboxylic acid methyl ester), the leading pharmaceutical drug for impotence.

Yohimbine.HCl [Y1002] 
Description: alpha2-adrenoceptor blocker.
Chemical Formula: C21H26N2O3.HCl
Molecular Weight: M.W. 390.9
Solubility: Soluble in Water (10 mg/ml).
CAS Number: CAS [65-19-0]
Handling: Store in Tightly Sealed Vial.
Storage: Room Temperature.

Trying to find usable indole sources, I do not claim to be a chemist by any means so forgive me if this indole has no use.
Not a chemist I just follow directions on the box mix

[Lilienthal]

It obviously has no use as a precursor.
Like the jasmin oil.